Hey, I’ve spent 6 years at Unity and am now at Defold team. So0o I might sound biased =]
I feel, today Unity covers OK maybe 95% of use cases for games, while Defold may cover like 5% of what you may want to do. But does it extremely well. Today Defold may feel like a homebrew solution that is heavily optimised for certain kind of games and skill sets.
If you have a small team of skilled people working on a 2D game with web and mobiles in mind, than you should definitely consider Defold. This is the case where the engine shines at its best today, outshining, probably, everything else on the market.
I am happy to follow up on this thread and discuss the game you have in mind from the tech and workflow perspectives. Defold may or may not be the best solution =]