This is a tricky question for anyone to answer - not due to its brevity, but rather because of how specific this will be to your company and your objectives.
Early-stage companies are deeply personal. A good place to start is to figure out just how important the benefits of this accelerator would be for you - and I'd challenge you think about the average case and worst case, like a programmer would.
How truly important is ____ (benefit of accelerator) for your company? How invaluable is it for the office space, connections, and referrals they may give you? If it's funding that you need, how much do you have to give up?
Accelerators are certainly what you make of it. My personal suggestion would be to have a serious heart-to-heart with your cofounders and team about just how valuable you all think this accelerator will be.
Much like Paul Graham says, don't get sidetracked by things that don't matter. There are only a few things that truly matter for your company:
You should be able to objectively answer how the accelerator would be able to concretely help you on these fronts.
Focus on the things that matter.