I have Snow Leopard on an older MBP and Lion that came installed on my new 2011 mini. I have nothing whatsoever against Lion, but at the same time, not a single thing about it compells me to pay to upgrade my MBP to it. To tell you the truth, aside from Launchpad, I don't notice that Lion even is different from Snow Leopard in my day-to-day usage of it. It's just completely underwhelming overall.
The fact that Lion's required for iCloud is really the only thing making me consider it now on my MBP (I sync my iPhone and iPad with my laptop, not my mini). And to that end, it feels like Apple made iCloud Lion-only for no other reason than to encourage more Lion sales.