The first thing I identify when pricing a kilt is Hand-sewn or machine-sewn.
Honestly, I don't care. I know some people put a lot of stock into that because it's a traditional way of making it. But I couldn't care less what methods are used, as long as the final product looks good and performs well.

You might try looking at what each vendor does that is unique and determine if that is of value to you. For example, Freedom Kilts is the only one I know of doing side slash pockets in tartan kilts right now. If that is a feature that you might want, then they stay in the mix. If a box pleat kilt is what you really want, then Matt would have to be at the top of that list. A double box pleat? Lady Chrystal suddenly is coming on very strong.
Nah, not interested in anything but a traditional knife-pleat 8-yarder. No bells and whistles or pockets or fuzzy dice.

Thanks for the suggestions so far. There are already some I hadn't heard of before.

Colquhoun Weathered would be a special weave as it is not available in stock from any mill.
Uh oh. I was under the impression that it was available in Lochcarron Strome. Do they not offer it even though it's listed on their site?