I used to ride '05 Slingy Fuels but have swapped over to an '09 Torch.
Depower throw is huge, useful range is good, both pop and grunt are ok/good on the '09/10 Torch but the '05 Fuel was better... BUT in anything other than perfect conditions the Torch wins hands down.
I ended up selling my 11m '05 Fuel after buying the '09 Torch 12m as i found the Torch far easier to get a good session out of. When the wind was a perfect 17-18kn with minimal gusts then i'd without a doubt take the Fuel, but given we rarely get perfect conditions i'd end up taking the Torch out.
Hadlow Pro's are very different to Fuel, Vegas & Torch. Definitely need to demo one as i can only try and explain them by saying that they don't have a depower throw of sorts, so much as a turning speed adjuster. ;)
Vegas's are alright but not my thing. They're a similar feel to the Torch but with less depower. Can't comment on the more recent Fuel's as i haven't flown one since they swapped back to 4-line.
C4's... well i still haven't ridden one.

They seem to split the crowd in that there's some people who think they're the best thing around, and then there's those that just say they're trying to be too many things to too many people. The best comment i've heard about them is that they're a great kite 'but they aint no hardcore C'. A fair few local riders have jumped ship to the C4's and absolutely love them... but they don't seem to be riding as well as they used to on their previous quivers. A very subjective observation, but that's how i see it.
... for me, everything gets compared to that '05 Fuel 11m. It's my yard stick on what makes an awesome kite.