Is eprom is getting obsolete?

Yes.. (although its still widely used)...

And how much it takes to erase in UV light?.

depends of many factors..how strong the UV source , how many times the chip has been erased previously..
(in my dual tube eraser it takes anywhere from 2-6 mins)



Use flash if you can..
ISP based flash leads far quicker development..(see Erik's "No Touch" articles..

IMHO- If you get a Cygnal starter kit , you will not regret it... even if you only use it to debug portions of code before transferring to another variant..