Past two days have been greatly improved here in Vegas as well. I haven't run a speed test, but I have had 3G data all day, with one time I had to turn it on and off (could be my modified ROM's issue there).
I do buy VM/Sprint's claims they are upgrading, it makes sense based on both the postings here, and previous releases of phones and or services by all the major carriers. There is always a bump when dealing with a popular new phone.
I can understand why this particular roll-out may have had extra problems. A large number of new users on an unlimited data plan, all buying new phones and installing tons of free apps from various markets, and testing and tweaking the performance of their new toys, I mean phones. Just the bandwidth to browse the app store is probably huge! Add to that all the fancy new Google apps that use voice, which has to be sent to their servers for processing, it's like a tidal wave of mini mp3s.
With the price of this service being so low, and the last two days showing improvements in 3G performance, I think the wise move is to wait 2 months before making any decisions (at least wait the one month you paid for when you activated your phone).