Allograft is OK, but the long term results would suggest that they do not stay tight as long as say patellar tendon or even hamstring tendon reconstructions. They all have their own advantages and disadvantages.
The bigger question remains as to why you might even need surgery. If your knee is stable and you have a good ROM after PT, there is no documented urgency to having an operation. Just because it's torn doesn't necessarily mean you need to have surgery right away, if at all.
Before people start chiming in about how great their own surgery went or how well their aunt did after a similar operation, nothing matters except your own symptoms. At the very least you should be asking your orthopaedic surgeon: what are the relative advantages of hamstring versus patellar tendon versus allograft reconstructions. And, why does surgery have to be done now if I have a full range of motion and no other symptoms. There is some evidence that with an unstable knee, ACL reconstruction might help to prevent the development of arthritis, but this is more in the case when the knee is unstable and symptomatic.
As a caveat, it is not uncommon to tear your meniscus when damaging the ACL, but perhaps simply debriding the meniscal tear might be adequate in relieving your symptoms, which is a lot less surgery than an ACL reconstrution.
I'm sure you will get a lot of anecdotal advice from people who have undergone the surgery, but this is an N of 1 ("I had this done thirty years ago and I've been great/terrible, so you should do the same as I did back then").
My background is as an academic orthopaedic surgeon and knee specialist with 20 years of experience. Even with this experience, I am not suggesting a course of action, but rather questions that you might consider asking of your surgeon.
Good luck.