I love my sub37.
I also have a phatty as well but its not the same thing without the duophony, and can find uses for the 2 that are seperate and have worked out ways (with the chorus of the A4) to make them sit together in a track even though they are voiced the same.
The thing i love about the sub37 is that it begs to be interacted with, the interface is such a pleasent experience you cant keep your hands off it. Im not a keys player but its making me into one, slowly…its still my favourite synth. Not that versatile, but lord does it do what it does well. It just begs for your attention and gets it.
Now, saying that i recently bought an A4 mkii, and sonicly it can do the sound close enough, and a shit tone more…its just more menu divey and less “experiential” and less imediate. But cover 5 times the sonic territory. With the effects its a far better choice, and so is the Dave Smith if choices are what you want.
You wont regret a sub37 if you get one, its my benchmarch from which i measure all other gear in many ways.