I haven't heard any complaints about Cygolite Hotshots from local friends. Mine have performed as expected.
My Hotshot 150 is going on two years of regular use, day and night, and has lost only a little runtime per charge. At night I mostly use the "zoom" mode with slow pulse, kinda like a road hazard light, which draws more power. It'll last for my usual 4-6 hour group night rides, but when new would go a couple of rides between charges. In various pulse/strobe modes it'll last several rides between charges.
My first Hotshot, an SL50, was new/old stock when I bought it. Worked great for a year, then wouldn't hold a charge. Still not bad for around $20, and cheaper than the batteries I'd have replaced over that time, or the good quality NiMH rechargeables I'd have needed. I went through a lot of NiMH AA's as a photographer and with heavy use they're good for about a year before the runtime per charge diminishes.
And Cygolite Hotshot prices tend to be lower than MSRP at REI and elsewhere, so even as disposables they're really good values for 1-3 years. Much lighter than my various AA and AAA battery powered taillights that I use on my heavier hybrids.