Well back from park so now feel qualified to post an opinion on this!
Nemesis is a different kettle of fish altogether so comparing them is tough. I have to say for me personally I LOVED the smiler and I think it does top nemmy in terms of the actual ride and layout. I was really worried reading all the reviews saying the smiler was smooth - I like my coasters to really chuck me around rather than glide round the track so I for one am gratefull of its roughness
and the final loop before finishing at the station is absolutely to die for I loved it!!!
That said in terms of finish and attention to detail nemesis wins hands down every time. I took someone with me today who hasn't been since before nemesis was built (!) and too see her reactions to the red water, the bus and all the rest of it was fabulous.....I guess us lot are so used to the old girl we perhaps take stuff like that a bit for granted. The one thing that ruins nemesis for me is those god awful cheesy announcements when in the station - I hate them!!!