Hi Matt, my advice is to have as clear an idea of what you intend to use the machine for and have a demonstration of each based around your specific needs. $30K is a lot of money to spend on the wrong machine for your purposes. I applaud your decision to go for one of the established brands as I believe you will encounter fewer problems and get better value for money, the issue for you is find out how much of the sales pitch is relevant and which machine features will be the most useful to you personally.
Historically, because it's a highly competitive market for the main manufacturers, some features were designed in to make the machines appear to have an edge over the competition. In practice, an inch or so in work area is probably not going to make much difference. It's a useful sales tool. It's for you to decide if you are actually going to need it or not. The same goes for the depth of travel in the Z-axis. Do you actually need it? Why would it be an advantage to have it?
The issue of engraving resolution in my opinion, is a red herring. Unless the manufacturer has a lens that can resolve to a small enough spot size to make use of the higher resolution, it's a pointless irrelevancy and one introduced to make the machine appear to be better on paper.
Do you think you will need a fiber laser at some point, and will it be worth the extra $30K for you to have it? If you do, keep it on your list. If you don't, discard it.
It's interesting that you are wary of Epilog's two-year old job control system but not of the reliability of Trotec's ceramic core laser which is newer, and potentially more of a headache if it goes wrong. Software is always being updated and improved and shouldn't cost you anything to take advantage of. See which one you find the most straight forward to use for your specific needs.
Try to find out what you can about the supplier. How long have they been selling the machines, how viable a company they are and what their staff turnover is like. Technical expertise takes time to learn. Good support when you need it is worth its weight in gold. Find out what the warranty entails i.e. whether labour cost is included and if not, what the servicing rates are going to be.
Compare the cost of replacement tubes, lenses and so on and try to tie the dealer down over turnaround times. You don't want your machine to have a long downtime for want of a replacement part.
As for MAC compatibility, I'd be very wary of any claims that salesmen make in this regard. If you can, get them to demonstrate it before taking it as read.