I used to have a PRO-2004 back when they were new. I couldn't afford it, so I used Radio Shack's layaway! Took me about 3 months to get it, but it was worth the wait. It never gave me a day's trouble in the 5 years I had it. Did the speedup, 400 channels, and unblock mods on it too (used to do electronic assembly, piece of cake). Picked up an old PRO-2006 for cheap in nice shape about a year ago.
I have several PRO-2021s. Although they don't go above 512 MHz, they work great, there's still tons of stuff to listen to between 30-512 MHz, and you can pick them up for practically nothing anymore. It's a real easy mod to replace the Motorola connector with a BNC... mounts thru the same hole, perfect fit.
I also have a PRO-39 Hyperscan handheld. Goes up to 960 MHz. I put a Watson 889 whip antenna on it, and it's a real DX magnet now! Great antenna. Haven't gotten around to unblocking it though.