There's plenty of pros who recommend Serum, and for good reason.
This is the synth I didn't even know I needed.
Having been guilty of G.A.S. before, I was skeptical at first, but once I opened it up in my DAW I could tell it was something special.
First off, it looks amazing. The GUI is top-notch, with spectacular animation for all modulation, and the ability to view the wavetables in 2D and 3D is something special.
It's a breeze to add modulations, which is becoming a nice standard it seems as there's a lot of movement away from the dependency on typical mod matrices and more like a classic modular drag and drop approach.
It's one of those synths that makes experimenting fun, and not a chore or a bore.
The ability to use custom wavetables, and edit them within is exceptional! No need for any external editor, as Serum's own editor is quite usable.
Even the huge list of filters and FX sound great.
I'm just going to go back to Serum now, it's too good to be more than 10 minutes away from, I swear.
If you're unsure if you should buy it, just do it. It's not going to disappoint. I will definitely check out the other Xfer products too now, it's that impressive.