I got in a somewhat uncomfortable discussion on another forum when I expressed my frank (poor) opinion of the Dirty Girl Gaitors website, http://www.dirtygirlgaiters.com/
I mean nothing negative about the product, and only heard positive things about it in fact from one or two users, but when I went to this site interested in finding out about the product, I couldn't find details or even figure out how I would buy it even if I wanted to.
On the plus side, I really like sites that clearly give accurate weights for items (like BPL does, "BPL certified"), to include how the weight varies by size. Better yet, when they help me find all the information I want on the product, to include product reviews (professional and/or by users) and a pointer to an online owners manual for the item if such is available. And of course at least one picture. A pointer to the manufacturer's website is helpful too.
One site that doesn't always have the lightest gear options (but has some good offerings) I like for the limited set of gear comparison charts they offer, for example the one for tents:
If only this had all the choices I like on their charts, it would be highly useful --- you can sort it by weight.
I *really* like it when --- typically the smaller shops --- offer above and beyond help, such as Henry Shires giving away some tent designs for DIY'ers on www.tarptent.com, and their sometimes competitor six moon designs doing the same, http://www.sixmoondesigns.com/ultralight/default.asp
I really like it when manufacturers think carefully through user questions and provide a FAQ, and even better when they add to the FAQ over time as they get additional questions.
I love it when a gear site tells me the availability of the item. I hate it when --- as I experienced recently with backcountrygear.com --- the availability data they provide is misleading (better don't provide it than mislead). The folks were very nice on the phone though, I've liked shopping with them otherwise.
Easy to go on and on with this topic; I'm sure that many others have a lot of examples of both good and not-so-good.