Personally, I'll never buy a Podunk Vidcard. GF2 MX for $99.00? Not for me. When you buy cheap, you'll often spend much more in aggravation. And a lot more than $50.00 of aggravation. While less expensive always looks like the smarter choice, often it's not. It's up to you.
The GF2 GTS really comes into its own at large resolutions. For 640x 480, or 800x600, the expensive GF2's give you no practical advantage over the GF2 MX. The benchmarks at smaller resolutions are almost the same for both classes of GF2's.