I'm thinking of getting a low power scope or Red Dot system for my 20" Bushmaster with an A2 top.  I mainly want it for target shooting for longer distances, sayt 100 or so yards.  

I'd like a low power scope, like a 5X, something that is physically small, like the ATN .223.  I like the size of the Red Dot systems but they look like they are not really made for accuracy.  They seem to inhibit the shooters view when shooting targets.

What are your opinions?  Are Red Dot systems good for accurate target shooting?  Which models should I avoid?  I really don't want to spend more than $200.

If you're looking to hit center mass out to 400m a quality "Dot" optic will be fine.

If you are looking to take an eye out, then a magnified scope would be better.

As far as your spending limit, you can find older Aimpoints (I've only used Aimpoints and I'm very happy with them).  I paided 175 for my Comp M.  You can probably find a Aimpoint 1000/3000 for less, which would fit your needs.