I would never buy a manual roll up screen unless you truly are ready to throw that money away and replace it, like clockwork, every year...
http://www.bigscreenforums.com/forum_topic.cfm?which=3448
The reality is that roll up, non-tab-tensioned screens will gave waves in the fabric over time. Some are better about it than others, but it still won't provide nearly the quality that a fixed screen, painted screen, blackout cloth, or tab-tensioned screen will give you.
I've used screens from Draper, DaLite, Stewart, Carada, and Focupix. I've also built a blackout cloth screen myself (with excellent results!). The fixed screens from Carada are easily as nice in build as what I've seen from Stewart, but Stewart has some nicer surfaces available. Focupix wasn't built as nice, but the material was decent, and it was well worth the money. The DIY screen was nice, but took about 10 hours to build, including the velvet wrapped frame, and cost over $100 easily. I wouldn't do it again considering that Focupix screens are easily comparible and more similar to a pro model vs. a DIY model.
I would consider them over building a screen because their quality is solid enough and they are far easier, and far more professional than most DIY options. Keep in mind that many DIYers build a screen, then don't know how to make a velvet frame to cover the screen and to square it off properly. They may just use velvet tape, which looks decent, but not as good as a proper aluminum frame. Also, the screen often can't be removed or packed up if you move.
I'm a huge fan of Carada, but would strongly recommend Focupix based upon your budget. I would also ask them about getting replacement screen material. You may find that you can get replacement material for 50 or 100 bucks and then you have a back up easily available if you do run into issues while still owning one of the best possible projection formats available to you.