Hello..
I am the owner of two OF2000's.
Q1. There is an adapter plate which you can mount the 2000 to and then mount this to the guide rails for routing. There are also stops available so you can do just that.. set a stop. In addition there is an accessory which allows you to rout perfect squares. It comes in two sizes, but has nothing to do with the rails. For a lot of groove routing I actually use the Domino, particularly for things like 5 or 6mm inlay or trenches for the bases of boxes. Its a more flexible tool than you think.
Q2. Before the OF2000 I used a Bosch 1100POF. Its a little 1/4" collet beast. The OF is extremely powerful and easy to use. Soft start and when you stop and restart immediately, it doesn't jar. I bought them originally for use with a Leigh FMT and D4R jig. They work beautifully, have 1/4", 8mm,12mm, and 1/2" collets available and are ergonomic in their use. With a Festool or similarly powered dust extractor, the job is very clean. The variable speed is cool too. I actually intende to buy a couple of Makita 3612c electronics, but for hand use they're just a bit clumsy. Everything on the Festool is exactly where you want it. If you want a real good routing experience, I suggest you get hold of some of Festool's 8mm shank bits. The results are outstanding. I'm sold on 8mm now for anything I get in that size shank. Spiral upcuts are the bees knees.
Incidentally, I have a Triton TRA001, 2 and 3/4 HP router in a table and I'd have no hesitation using the 2000 in it's place. Power to burn. Sorry I forgot about the price. Yes I think they are worth it. Over here they sell for double the Mak 3612s but I don't regret buying them.
Hope that helps.
Regards,
Orson