I'd also add the Phanteks TC14PE for best air. Comparable to the R1 and D15 and usually less money.
What about the TT 360 for water?
Addition: FUMA for "Best Air"
Addition: Cooler Master ML240L for "Best Budget Water"
I am about to buy an ML240L. Dropped to $59.99 a couple days ago. Fantasic deal for a 240mm AIO that actually has pretty good professional review.
Lowest I've seen is $50 after rebates. That's just crazy cheap for an RGB cooler, let alone a 240mm one with decent reviews.
Actually, both of those are outperformed.
The Mugen is edged out by the Le Grand Macho
And the H100i by these
There is a mile long list of better AIO's than the H100i. Zero idea why people even buy it anymore.
And a whole lot of 240MM AIO's have very similar performance to it.
For the Mugen 5 sure its out done by a bit by the Grand Macho but the Macho costs nearly twice as much.
To be fair, OP didn't give any constraints other than "$120 or less"
But yeah, for a full decision, more information is definitely needed.
idc what size, just the absolute best.
You kind of have to fit it in the case. Or, are you not looking for one to actually use?