I bought this synth in 2013. I love this synth. I've played around with a lot of other synths and I just always come back to surge. Why? I actually have fun programming sounds. I don't want to open up a synth and feel like making something is a chore. At the end of the day it doesn't matter how much power a synth has if I'm fighting with the interface. It seems like today people are so obsessed with the next big thing and power, that simplicity and ease of use is seriously overlooked.
Surge has it's own character. You either hate it or love it. I'll admit at first I was a little put off by its harsher sound, but with a little tweaking you can definitely get some warmth from it. I find it's incredibly flexible and a great all rounder synth.
The other thing that's great is Surge finds a balance between being too heavy in a mix and too thin. When I design sounds I want them to fit. When previewing a patch alone in surge it might not pop out at you, but 9/10 it'll fit in the mix with minimal tweaking. I'm not a fan of the presets that sound amazing on their own, but eat up the whole spectrum that happens a lot on other synths. With Surge it's like fitting pieces of a puzzle together and when the track comes together it's sonically beautiful.
This synth strikes the perfect balance between being complex enough to make some awesome sounds and being user friendly enough so you spend more time making music and less time fighting with the software.
If you're thinking about buying Surge, don't hesitate. This is a beautiful synth with so many possibilities and an interface that just makes sense.