We are out there, and we have a pretty good web presence... on a par, I'd say,with the number of glider certificates issued. A lot of us transitioned from power, too.
Here's my story:
Got my PPASEL when I could barely keep up with my bills, let alone afford to rent or buy and airplane. But I wanted it; wanted it real bad. I made it happen, somehow.
Rented from FBOs for a while, found a club (which was a much better deal overall), club and I both moved farther away from each other, 2001 crushed my hopes of moving up a few notches financially in my career at the time... couldn't afford the club, especially with the commute to that airport. I then stopped flying for 4 years (shudder).
Couldn't stand it anymore, got back into it. Started making more money, got my tailwheel endorsement, looked into getting a loan for a good 2-seat taildragger about the time the latest "depression" started... got discouraged.
Thought about finding a partnership, but then my work situation tanked even deeper. Ugh.
During that period, I discovered there was a little glider club based where I was renting Cessnas. Met and made friends with some of the members, got lured into a ride, and found exactly what I was looking for- not just in terms of cost, but in terms of some flying that would really challenge my passion and whet my appetite for real enjoyable flying (instead of logging another couple hours alone going nowhere special because plans to share expenses with friends had fallen through yet again). The key things, with this particular club, are that instruction is free, and there's no hourly rate for glider flight- once I got a handle on the flying, my hourly cost depended on how much time I could get off a given tow. It's a powerful incentive for a guy on a tight budget.
My experience so far with this club is probably not typical, but it's definitely worth a shot for anyone who is interested in gliders. Most glider pilots, even those who divide their flying time between gliders and power, will tell you it's addictive and very rewarding.
So how does the training compare to ASEL training? Very similar, really. You may very well make a series of short hops on a given day...depends on the number of students, instructors, towplanes and trainers available.
But it's different in that you won't just work on any one aspect on a given day. Every flight (assuming aerotow) involves staging the glider, the launch, the tow, the release, some maneuvers, maximizing performance, learning to use cues other than the instruments for target airspeeds, etc.... planning ahead for the pattern entry, flying the pattern, making a precision landing. Glider training is quite simple in comparison to power, but consistency and precision are vital, because after release, it is an "engine out scenario". And if you want to work thermals or ridge or wave lift, or fly XC, you can't be sloppy, in thinking or handling the aircraft.
On my first glider lesson, I didn't fly the launch or tow, but was observing very closely. After release, I made my clumsy effort to make some decent turns, fly at target airspeeds, and fly the lower and closer glider pattern. My first landing was assisted. Barely 20 minutes from launch to landing, and it cost me 40 bucks ($10 for the tow plus $1 for every 100 feet before release- we went to 3000). Made three more flights that day- boxed the wake, more turns, etc... by the last flight of the day, I was doing pretty well. Paid $160 for less than 2 hours total... if it was a bigger club with hourly rates for glider and instructor, it would have been worse. But I was having so much fun I didn't care.
Second day was different- gusty xwind, so the first flight was all about learning to deal with that. But on the next flight,because the thermals were booming, the CFI suggested we try to work some lift. Normally, working thermals comes later, but it was too good a day to pass up. With him demonstrating for a few minutes, then handing the controls over, in a while we'd gained 1000 feet. Then we did some slow flight and stalls, then worked another thermal, etc, etc. We landed after about 1.5...
that flight also cost me $40. Next time I flew, we made two flights, each about an hour in length. On the second one that day, we got to 5200 from a 3000-foot tow.
It was definitely looking better now from a cost perspective, but meanwhile I was just enjoying the challenge of dealing with all the little differences, and really getting excited about maximizing performance from an aircraft with no engine. Maximum time aloft requires very consistent coordinated flying, thinking ahead, reading the sky and other lift-producing signs... and from the moment of release, you are committed to an engine-out landing, which really wakes you up, to say the least. It basically adds a whole new dimension to flying, and certainly to flight training.
We don't really get into XC flying, and interestingly, you will find that to get the PPG, even without prior ratings, XC soaring is not a big requirement. You need to understand the basics of navigation and how to make decisions based on altitude, glide ratio, wind and lift or sink, but flying tasks, completing "badge fights" or competitive soaring is another plateau that rated pilots pursue without much scrutiny by the FAA. Nobody goes to that next level without instruction or guidance from those in the know, but the PPG checkride does not stress that part of things. Even working thermals is not a requirement. The practical is usually two or three flights: box the wake on tow, deal with a simulated rope break on climbout, do some stalls, steep turns, turns to headings, fly a good pattern and land within 200 feet of a designated spot. You might have to do all this with the altimeter and ASI covered. That's pretty much it.
In essence, glider flight is not easy, but it's very simple.
Anyway, I started 5 summers ago, and now I have the PP-G and commercial (we give rides to the general public, and the commercial-rated PIC gets a free tow), and if all goes well, this year I will get the FAA's blessing to instruct. I'm pretty proud of these milestones.
I've racked up some time in our single-seater, too... it's silly, I guess, but that's a big deal for me, because nobody can check you out in a single-seater. Heady stuff, flying something like that for the first time.
The social aspect of hanging around with the club on any given gliding day is a big plus, along with the rewarding challenge of making flying a team effort. If flying is only about going high and fast from A to B, it's not for you. But if you like all the other stuff, you'll love glider flying.
The only real problem for me has been making all the pieces (schedules, weather, etc) fall together often enough to make me happy and keep moving forward... but that is no different than with power, except for the fact that you always need at least one other person, for any kind of tow.
I hope you give it a chance. You might also learn more if you look here:
http://www.ssa.org/
...especially in the pattern (and even on the weakest days, there always seems to be lift in the pattern... 
). 
