I recently purchased a stereo pair of these microphones from digital village, for £320. They were B-stock but were returns and looked untouched, and came with the same warranty, they normally retail at about £480 though.
The other microphones I was considering instead of these were the Rode NT-55s, Oktava MK012s and Audio Technica AT4041s.
I liked the oktavas most out of the others, but preferred the SE4s, as I found them more rounded and to have a slightly better transient response.
Up until I got these, I'd mainly used C451s as my go-to SDCs, for acoustic guitars, snare bottom heads and occasionally overheads.
I found the tone of the se4s pretty similar to the 451s, but preferred the slightly smoother tone in the upper mids, they seem to compliment cymbals and hi-hats a bit more.
I've also found that they sound great on acoustic guitar - great clarity and punch, and absolutely love them as my drum overheads - they just seem to make everything gel together so well.
I have had varying success using them for slightly weirder applications (pointing down from above a vocalist's head, vocal room mics, and on certain guitar amps).
They came with just the cardioid capsules, although you have the possibility of buying hypercardioid and omni capsules to use aswell. I decided not to get the extra capsules and doubt I will as I don't really have the need for them.
They also have a switchable low cut filter and 10/20 dB pad that are both extremely useful.
They come in a great, sturdy case, with a stereo bar included, which is a nice touch. The case also has spaces cut in the foam for the alternative capsules (quite cheekily I think, as whenever I see them I get tempted to buy the capsules haha).
Anyway, overall they're great mics, and I would have bought them even if I hadn't seen them on offer, and would definitely recommend them as a great SDC for any small/project studio owner.