I'm changing my mind pretty fast these days. Forget omaha, I'm a SNG guy now.
Basically I think even though in omaha you can get a lot better -since there is a lot of room for skilled players to get an advantage from other skilled players-, I believe in sngs, you can get amazingly strong -and be able to get a great hr/rate- in relatively small time of study.
This leads to an obvious conclusion: If the pool of fishes begins to get small in relation to the regular's pool, it would not be that bad for omaha players, as they will continue to get lots of value from less-studing regulars. On the other hand, it would be terrible for SNG regulars, because as I stated before: I believe strong regs can only get a small edge vs less-studing regs on SNGs.
So puting this into 2 simple graphs:

Those are really far from being on a valid scale, but the point i'm trying to make goes beyond that.
The thing is, from one side, that you could pick a random dude with some grasp on maths, teach him in one month to play, and he will probably be able to get some money from sngs, and that money being somewhat comparable to the money good regs make. In omaha he will probably struggle to even beat the games, because that one month of studying is not nearly enough. And let's not even start talking about the difference of edge between this guy and the best omaha regs...
That's analizing how a new timer (me for example) will do on the short-term on both variants of poker: SNG wins, flawless victory.
But from the 'future of the games' perspective, seing the graph I put there, it's obvious that in omaha, even if you are already a skilled player, you have great money-incentive to study, as you get a real advantage vs the field (that is specially appreciable if the fish situation drops down).
On sngs, on the other hand, if fish's pool drops, regs won't find an money-incentive to study, because they know edge between regs are pretty much capped by the icm equilibrium (there still lot's more to be made other than nash, but you get the picture). So if fishes go down, and stars does not adjust rake accordingly (down of course), regs will struggle to get money before rakeback, and they will probably start migrating to some other markets (like omaha, cash games, sportbetting, forex, or any other crap).
That being said, I think studing sngs is the best option in the shortterm, there are still lots of fishes filling lots of different -but if studied holistically, basically all the same shit- types of sngs: hypers, fiftys, 18man or any other. In the meantime, studing omaha in spare time is fine, if it's for fun + future ev, but not just for the 2nd one.
So from that horrible tl;dr speech, cliffs are:
SNGs: Great value on studing them on the short term, as they are still plenty of fishes (table selection gains value if you don't mind multi-game, which is my case).
Omaha: Shortterm studing does not get lots of value, but it mantains it's value over the time, that's why skilled players can make lots of money even on non-fished tables. Great value if SNG fish's pool drops down for some reason.
I'm going to be playing any variant of SNG that has fishes. I plan to get Platinum this month and I'm pretty late, so it will demand some grind.
I'm evaluating geting sharkscope hud, any thoughts on that?