That's a good question! I only have a few minutes so I won't be able to answer your question thoroughly...
Generally speaking snow cats were purchased new by three distinct groups. Utility companies, governmental agencies and ski areas. Utility companies tend to put few hours on their machines and maintain them very well. Ski areas put lots of hard hours on their machines and maintenance/repairs can be downright poor. Governmental agencies tend to be closer to utility companies, but in my experience not as good. I've owned three Tuckers, ironically one from each of the groups I mentioned above. I'd look for a machine that was owned by a utility company. There would have to be a compelling reason for me to buy anything that was used as a groomer.
Here's a link to a treasure trove of manufacturer specification sheets. You can learn a great deal, and narrow your selection down, by checking out some models you might be interested in:
http://safetyoneinc.com/snowcats/snowcat-manufacturer-specification-sheets/
If you're interested in a Tucker I'd encourage you to call them directly (1-800-SNO-CAT1). I've talked at length to both Dan Dressler and Jeff Godard. Hugely knowledgeable guys who are generous with their time.
Lastly, have you considered a UTV on tracks (such as a Polaris Ranger)? While bone stock they have few creature comforts, but a dizzying array of options are available (at significant extra cost). I don't think they have the capability of a true snow cat, but one of those may meet your needs. Gotta run...