Johnny's says Mountain Merit does not taste as good as Defiant in their description of it. I'd guess it was bred mostly for disease resistance.

[QUOTE=heirloomtomaguy;623538]I know i wont be growing it any time soon. Way to many better tomato varieties to choose from.[/QUOTE]

Exactly.

[QUOTE=Gardeneer;623497]…
[B]What do you know about it ?
Have you grown it ?
How do you review it in terms of taste, production, growth habit, disease issues, etc. ?[/B]
…[/QUOTE]

I have grown it (in 2016 from seeds from reimerseeds.com).

It's still fairly popular. It's known for being fairly reliable, having kind of large fruit, having disease tolerance, being a hybrid, growing well in some areas, being prolific, having less-than-ideal taste (but some people love its taste), not being extraordinarily vegetative, etc.

It wasn't my least flavorful tomato, but it was one of the least flavorful of all the tomatoes I've ever grown, so far. Red Trifele Russian (not true to type, because they were round) and Early Harvest F1 both had considerably less flavor. Production is decent. It's not late. The fruits are a good size, but the most remarkable thing about it to me is that the fruits grow from small to large very, very fast; I haven't seen other tomatoes do that, to my knowledge. The plant isn't large. The fruits weren't mealy, if I remember. The fruits look and feel good. I saved F2 seeds. All in all, I really like how the fruits grow to size fast, and I think breeding new varieties from it is a good idea. It's a space-saving tomato, but larger than a dwarf.

I imagine it would taste better dry-farmed and/or with less potassium than I gave it. I didn't dry-farm it. The fruits were shaded by foliage (I didn't stake it); so, it may taste better with more sun.