I've been trawling the Saints boards, they seem very much behind Pochettino even with a few caveats (that he has the perfect set up in all fairness, spent nearly 40m over the summer, plays more direct than Adkins etc). If we can't get FdB or the likes of Favre right now, then we could do worse than throw some money his way - he knows this league by now, he had an instantaneous impact at Southampton (so good translator of ideas?), and philosophically he and AVB share more than a little of the same DNA, in theory at least (full court press, 'vertical' football, spending most of the time in the opposition half etc). I have no idea of his man management ability and we have some serious confidence issues to work through, but he did replace a popular manager in Adkins and seems to have gotten the players on side quickly even with the language barrier.
I don't see much difference between him and Martinez in terms of risk - both coming from lower sides with less pressure, both with clear and stubborn philosophies, and both with plenty of investment (Lukaku and Deulofeu would cost ridiculous money if not on loan). You can't predict who can make the step up in this league (look at Moyes right now), but I think it's a good sign that Saints are clearly coached and have shown the ability to play fast, fluid team football. He's not a super-glamorous Total Football name from Total Football league, but he's young and the fans believe he can go on to do great things, which is a rather different attitude than Everton fans when Moyes got promoted.
That said, I think Pochettino would have to be either idiotic or insane to leave Cortese and his cozy set-up at Saints. No expectations and remarkable amounts of money. If he wants to climb up in this league though, I don't think any other top 6/7 position will open up soon besides Man United - and they will want CL experience this time.