Excellent business model, I get to keep the software I bought when the license expires. Never forced to continually pay for something you don't see value in updating. I think that's one of the key factors which drives them to continue to improve their products. If future version of their products wasn't vastly improved over the previous then people wouldn't upgrade because their current version serves them perfectly fine. And if you don't like this years update, maybe you'll like next years. No downsides whatsoever.
Never used any of their TeamCity/Spaces stuff but it looks cool. I can definitely say I'm a fan of their IDEs though. Use them every day.