No doubt the UI of WP7 is awesome...there are lot of limitations. Instead go for android, specifically i would say go for HTC Desire which is arnd 25k...awesome phone with lots of applications to be used.
HTC HD7 has already launched, it's available in Flipkart. So we can assume HTC Mozart is going to be launched soon. However, there's no specific date yet.
It's definitely worth buying... about the limitations, Copy-Paste is going to be available through update soon. Microsoft has assured that it'll make those functionalities available through updates as they require. Hardware is superb no doubt, as expected form HTC.
One thing that may bother you is that the no. of apps in Windows Marketplace is till now very low compared to Android or iPhone. So if you're interested in lots of apps, it'll take time.