No contest. Even at default, the GTS-V manages around 4.6 gb memory bandwidth compared to the MX maximum of around 2.8. Also there are many reports of people successfully clocking the GTS-V at standard GTS speeds of 200 core and 333 memory to attain around 5.3 gigs of total bandwidth. Trust me, I have had 2 Geforce 2 MX cards and now have replaced both of them with GTS cards. The difference is noticeable, especially if you like to play games at 1024x768 resolution at 32 bit color. IMO, go for the GTS-V and don't look back. if it is out of stock, go for the MSI 8820 for $97 plus shipping from newegg.com. Mine has been very solid (and I paid $125 for it!) But the gTS-V is the current budget card steal, absolutely the best bang for the buck, IMO.
Chuck