I had the local dealer fit 254E cams to my 2012 103 CI FLD Switchback last week. The bike already had a 2 into one with SE slip on muffler, SE high flow air filter and SE tuner with a map to suit, it was re mapped after the cams were fitted.

I've only had the chance to do one ride on the weekend (300kms) since they were fitted but it really feels like the cams have made a difference the the acceleration of the bike from about 2700 onwards towards about 5000(ish), it's definitely got more acceleration in the mid range and towards the top end.

On the other hand it feels a bit softer under 2000 (but I don't ride under 2000 anyway).

The exhaust note has altered too, it's got more bark both under acceleration and at constant revs plus a slight throb to it at idle, sounds a bit better than it did before I think.

I wanted to stick with a HD cam for warranty reasons and the 255 was aimed at the heavy touring bikes (low end torque) and the 204 seemed to be more aimed at performance bikes (high end power) where as the 254E seemed to fit the 'light tourer' highway use a bit better (mid range increased). 

I couldn't find many people on the net who had this cam so I was a bit unsure I'd like the result and It hasn't been dyno tested (and I'm not sure if I will) so I can't give you before and after graphs but my gut feeling is it was worth it.