The worst thing about them is the lack of patch memories. This is sold as some kind of creative limitation, but really it just means you can't park an interesting patch and keep refining and exploring it.
I prefer virtual modulars like Reaktor and Cherry Modular. Especially Cherry because there's a nice Java dev system which allows custom development with some ready-made UI and I/O options.
This is part of what appeals to me. You can have something you love, but you have an idea that you want to explore. So you have to tear it all down.
I'd usually be drawn to hoarding patches, and organizing them, and labelling and maintaining. With a modular synth, I can only produce in the moment. I find that really freeing.
I'm a hobbyist, and not a professional musician, i might think different if I did this to make money.