Well, I've a mate who's an F/O at VirginExpress (hi JFS) - and he absolutely raves about them ! He tells me that they seem to do a mixture of schedule and adhoc charters; Yep, he's a happy chappy.
I've also got some mates at 'Go' - and I'll come clean to having more than a passing interest in it myself - and we too think that it (Go) is the dogs doodaas.
I'm likewise sure the folks at both Ryan Air and easyJet will all concur that theirs is the best.
What does seem to be a common theme (imho) is the need for experienced LHS folks. That said, given the pool of F/O's many of these airlines have, you might find that they are tadge reticent to take Direct Entry LHS, for fear of hacking off the F/O's.
Of course they all look to be expanding, so send off those CV's (one page only).
It may pay to remember that what with the recent demise of AB and Debonair, plus the time of year (not normally known as a hiring time), you might not get a reply as quickly as you might like.
Ahh well, never hurts to apply - best of luck.