I always considered myself significantly better the average 180 (and later MTT) reg in general but especially postflop at the stakes I played so the jump was easier for me than it would be for most people. Part of the reason is because I had played a bit of cash (mostly 50-100NL) "earlier in my career" so that helped, and asking questions to some buddies like lissi helped (even though he isn't a cash player, he's just really sick at poker in general) and I guess I learnt/adjusted fairly fast. I still have a lot to learn and I want to improve. Fwiw I think the general adjustment from MTTs to cash in general isn't that tough because for most people they can just start really low and see how things go/move up fast etc. So someone who beats MSMTT could just start at 25NL. But most MTT players (see below) think they are better than they are - not directed at you, and jump into pretty high stakes relative to what their skill dictates and will do poorly.
I went into 500 straight away (gave it a go, ran decent at the start, wanted to make SNE, was willing to give up a little EV for VPPs as well as improving by playing with tougher players/games), so it was tough and I had some bad moments when downswing etc, but if I went into 50NL I would have crushed it straight away etc.

I feel quite bad answering this question because I'm very critical/harsh when it comes to MTT players skill, on average.. In short I think the average MTT player is pretty bad overall, even at mid and high stakes. Obviously there are (many) exceptions of guys who are really sick etc, but a tonne of the guys who win have just run way above expectation (albeit the competition in MTTs is also much weaker) and either don't realise or don't want to admit that the variance is so sick.

There are many reasons for this, MTT players tend to not need to work on their game as much (way weaker competition), and tend not to when they win/run good "because they don't need to", and tend not to when they lose "because obviously they are just running bad, since the variance in MTTs is so high" etc. In cash you just can't use variance as an excuse for losing to the same extent.

Honestly I think the average 200NL reg, which is considered "small-stakes" is significantly better than the average high stakes reg who plays stuff up to 109, 215s, 50rs and stuff and it's not very close. MS MTT is really soft and HSMTT is fairly soft whereas MS cash is ridiculously tough. I dunno I mean I think most people (both cash and MTT players) generally agree cash players are better at poker overall, and a cash player will adjust to MTTs much faster than the other way around.. I'd much, much rather put a mediocre 100nl reg into the big 109 than a mediocre MS player into 100NL etc.

Fwiw I still consider myself someone who plays MTTs so it's not likely I'm randomly hating on MTT players, I have a lot of friends who play MTTs primarily who I consider very good at poker and respect them a lot etc. Like a lot of people it just kinda bugs me to see a bunch of mediocre at best players bink the Million for 200K or w/e and suddenly call themselves a "MTT pro". The main thing is most people have huge egos and actually think they are good when they are running so good, rather than just acknowledging they have run good lol. Like someone who is good and crushes/wins all the money and has an ego is still a dick, but people who win and aren't good but think they are just tilt me I guess. You can call it jealously if you want or w/e.

Some of those clowns who just luck box MTTs with their massive egos jump into 500NL zoom and have no **** idea that they are amongst the biggest fish in the pool. I should stop tapping, and also emphasize there are definitely sickos who are exceptions to this (i.e. are +EV. guys for example busto_soon, wizo, munchen_hb, achen etc come to mind).

That's a bit of a tangent to your actual question I guess, so sorry about that. I think the average MS MTT player probably could beat 25NL full ring very slightly and probably lose slightly at 50NL full ring. Probably lower for 6 max. That being said it is about working hard. I'm not saying they don't have the potential to beat the game, but if I took 50 random winning MSMTT regs and put them into 50NL I think they would be a slight net loser at first. I would bet a lot against them at 100NL. Part of the reason however is that even the "good" or decent regs probably lack postflop (but may be good pre-flop, or better with shallower stacks, ICM, applying pressure deep etc - basically different skillsets).

Basically if you are interested in it, play some hands, see how it goes, post hands/ask questions you aren't sure about and improve. I'm very confident that like most things in poker, if you work hard and want to succeed you will do just fine. Fwiw you're welcome to send me hands/questions on Skype if you like, always happy to help. Gl, and sorry again for the rant, it's obviously not directed towards you and I'm again not hating on all MTT players as a whole.

I do realise this reply had a lot of negativity/hate in it or whatever, so sorry to readers for that. It isn't directed at any player personally.

because they can swim..