I've used Swype on my S4 since I got Android, I like it. I've found it fairly poor quality software though, for example:
- popping up a keyboard can take up to 10 seconds - though usually it pretty quickly this isn't unusual
- my phone crashes MUCH more often with Swype enabled
- I've been getting a lot of freezes the past couple of weeks. I've disabled Swype and my phone seems much more stable - early days though.
Google Keyboard has gotten a lot better, it's not quite as good as Swype in terms of word recognition but it's 80-90% and it's FAST. Fast to pop up, fast to respond, etc.