I have a LCA EZ-Green press and love it. I'll put it like this, no one, and I mean no one, will be able to put the time into fine tuning and tweaking your setup like you can do if you have one--it's just not profitable for them. One of my best friends in the world, and someone I trust with my kids, has a shop and even then I will not bother him to ultra fine tune my setup--it takes hours and days to tweak this, that and you. Can you out-tune your shooting abilities? Absolutely you can and many, many do, but that way you can only blame the Indian and not the bow. Let's talk about convenience for a minute. There is nothing more convenient than having your own equipment, especially when you have to take a few hours or if you're day to fix something you could have had done in a few minutes in your garage.
As far as not having the knowledge, that is easy and just tinkering around will gain you a world of knowledge and that is key to understanding the mechanics of the sport--it can make you better.
If you can get a press, and have a wife willing to let you pull the trigger, then I would've done it before typing this post! :D