All the snowshoes I checked out had load ratings attached. Denali has ratings cross-referenced for different kinds of snow as well as varying body weights. Using them for an example, the maximum they show for deep, soft snow when breaking trail is the standard 22" snowshoe plus an 8" tail. They're also only 8" wide, as compared to others that run 9", 10" or even more.
If you're over 200 lbs, with pack, I'd also look at strength and the width of your stride.
My biggest concern when shopping for snowshoes was whether they would flip snow up my backside! A lot of the more expensive brands, like Atlas, seem to have that problem.