I just got mines back from a pal who’d had a loan of it so he had something to use with the new midi out from his A4. He liked the ModalApp OK but didn’t particularly like the front-panel with it’s quirky diagonal layout. For me, I’m OK with both but the physical interface is a bit marmite. Sound-wise, I think it sounds really nice and I enjoy it a lot.
I wouldn’t say it’s a straight-forward alternative to the Argon8 as the oscillators are more traditional morphable analogue waveforms. No wavetables or processors available. If the wavetables/processors are what interests you then you can get the Craft2.0 which is much more similar albeit with a greatly reduced number of wavetables and it is only monophonic. I also also have a Craft2.0 which I like even more than the Skulpt - for just north of £100 it’s an amazingly flexible and great sounding monosynth. Especially when you consider that you can use the Spread parameter to create chords.
So, for me, having both Skulpt and Craft 2.0 means I’m able to resist the temptation of the Argon8. There is a review on YouTube by Stimming where he goes through both devices so that might useful for you.