Please refer to the following link (towards the end) for introduction
I have been listening to his songs for over two years now and they are quite a regular feature on my playlists.... I have always believed that the best test for 'good music' (as for numerous other things) is the 'test of time'. If you feel like listening/ revisiting a song after every now and then, over a period of few years - and still it sounds interesting and thought provoking - that would be its greatest testimony.
For Rabbi-lovers like me (Yes, I am turning into an ardent fan of his music), he is sure to be counted amongst the greats on the Indian music scene - and mind you, the instrumentals of his songs are rather 'popular' (in the sense that its not like listening to 'ghazals' which would appeal to only a particular kind of taste), but still they are nice, classy, rythmic and very tastefully done - but I think the key difference lies in the lyrics of his songs and themes he explores. Unfortunately, most of them are in punjabi so people who can't understand punjabi at all might just miss the soul of his music...
And I recently realised that his is definitely not a small fan club - in fact his music is acquiring a cult status all over (see this http://rabbism.blogspot.com/ )
And just as his thousand of other fans, I too am eagerly looking forward to his next album. Fingers crossed!