Oddly enough, I've owned both.
Currently have the Allez Sport 09 and I love it. Comfortable, solid and well built, but quite light too for alu, and the kit you get on it (Mavic CXP 22 hubs, Tiagra group) is ok. Not the best but solid and these days, yer pound doesn't go as far as it once did......
It is a nice ride though.
I had a Via Nirone 7 before this but it didn't last long. It was a touch on the small side for me I think and just didn't fit me very well. It may well fit others very well and folk on here seem to really like them. It didn't feel as 'solid' as the Allez, but felt quick. Sold it after 3 months or so.
I like spesh as a brand (not sure why) and would go for the Allez every time. Get a new seat though! The stock one is white and pretty basic.