I'll randomly spitball some opinions, let me know if you want specific intel. No idea on who does CAA at these.
OAK starts with Vector on Sep 1, so enshizzification intensifies soon. FBOs charge landing fees currently (which are pretty high, I can't quote them, I'm based -- but call first!). Class C = "good service" from NorCal outbound but it comes at that fees price. HWD IFR departures have to wait for OAK departures since HWD launches right up OAK's trumpet. VFR patterns for bugsmashers at HWD are goofy -- 600' AGL if I remember. IFR approach is cake.
The OAK surrounding area is hard ghetto before it gets better, so don't walk to your next stop. They have all the rental cars you'd ever want though, and both Kaiser Air and Signature try to be decent FBOs. Oakland has a BART connector if you're headed to the city. Unbeatable. BART finally takes credit cards directly.
HWD has a great FBO and also a good FBO, and good service generally (I like Meridian a lot more than APP but... both are decent) -- not many services unless you're planning to hop out of the light jet and walk to the local Target grocery. I'd call ahead if you have specific needs. Friendly blue collar area, nothing interesting nearby unless you're down for some Sizzler. (The Hayward Sizzler sucks, even as an ironic lunch stop -- there's a Five Guys and Jamba next to target)
CCR is definitely late to fog in and early to clear up. Concord call themselves "bay area" but they're really just Stockton West. Airport is suburbia. Taco Bell, starbucks, trader joes all within walking distance.
No real ATC delays inbound, Norcal is top shelf.
CCR tower don't have actual radar as I recall so you get dumped inbound and "squawk 1200, f off" if you're VFR in a bugsmasher. No idea if jets are treated like that.
HWD no landing fees. CCR not either. HWD FBOs are more "jet oriented" in my mind, CCR is pretty bush league. There might be a better FBO than Sterling and PSA. (those two are just like any midwest nowhere flight school fbo)
I've kept my plane at all 3, you really won't go wrong with any of them. I'd break the tie by considering ground services required and call to arrange accordingly.
$0.02
