Mine have been flawless so far, granted, they haven't had a huge amount of use. I run them through a full charge/discharge/charge cycle about once every 2-3 months, and they sit in stock mags waiting for power outages. Same goes for some Tenergy brand C size cells. My C and D size cheapo china cells have been really decent as far as consistency, and low self-discharge goes. They're the only NIMH cells I own that I can rely on to have juice in em, even after a month or 2. The rest are AA and AAA stuff, some powerizers, some tenergies, most of them have been ok, inconsistancy from cell to cell is showing up more and more with increased cycles, the energizer AAs are totally crap(from full charge to dead in 3-6 days resting), and some of my tenergy brand AAAs have totally gone dud on me.
For the money, I'm pleased with the Powerizer D cells. Though if you are willing to spend more, there are better cells out there worth a look.