I haven't had crashes (Mac G3 running System 8.1 and Motorola Starmax Mac clone running 7.6, both using Netscape 3) but I have had slow response time and the first-page voodoo they warn about.
As for getting a response from E-mails: about 2 months ago I E-mailed them about a blatant typo ("your" for "you" in "So what are your waiting for?") in the FlyerTalk intro page. Not only did I get no response, they haven't fixed it yet!