Like Gino said, they all have their pros and cons - and he's very right in raising the issue of service. Even if it's a good machine, but there's no one to help you with any problems or questions... you're in for a not so pleasant experience.
General rules to keep in mind...
1) knowledge base availability - eg info on signs101, online manuals etc. (stay away from unknown brands).
2) know the limitations of the machine BEFORE you buy. this sounds stupid, but if inexperienced you really need to look at all the small things from print width to media thickness to ink availability/price/longevity, print speed (don't be fooled by high numbers, they are usually based on low res printing which you'll NEVER use for wraps (99% of the time)... compare them at standard and/or high quality printing for real world numbers).
3) cost of maintenance - parts wise they might be similar, but back to the issue of service, if your nearest tech is 4 hours away, it's gonna cost you.
Anyway... best of luck.