I've used Tiled but not used Ogmo, but reading the bulletpoints the main upsides seems to be a more project focused approach (perhaps enabling more direct loading), in general though it doesn't seem to be too different (most listed features are in Tiled).
If you're starting fresh maybe try both before integrating on a coded workflow, but either will probably serve just fine for 2d games.
I always feel depressed when I see what is my developer work nowadays, but this kind of project makes me happy. I don't know exactly what it is, but those simple UI thingies with pixels are cozy to me.
Easy Integration - When you're done editing, save your level to a handy JSON file - one that is easily parsed to give you immediate access to all of the tiles, decals, and entities you've authored!
That still leaves a lot to be desired. Am I expected to write all the code to import this format into my engine of choice? That's not exactly "easy".
For instance, is there tooling to import into GameMaker? That would seem to be table stakes.
