"I think you are talking about a vanson speedy box, also called a BC1HU..."
I have one. Love it! I only use AA bats, and have had no problems at all.
What I like about it is that it is simple enough for my wife to use it.
Put the bats in: Red = not done, green = good. Flashing means (probably) a junk cell. Simple.
My only VERY minor gripe is that it can seem a bit slow at times...but, I think it tops of the batteries very well, and charges them safely.
I believe Silverfox has tested it thoroughly, and determined that (with AA bats), if you let them charge normally, but leave them in for a while to allow some trickle charging, the bats really top up nicely. (I believe he also stated the higher capacity D cells may not charge completely because of the time-out circuit, so you need to terminate charging and re-start to top them off)
I typically leave my cells charging overnight.
This mirrors my own experiences, as my Kodak 2500's (people have had problems with some of the 2500 bats) have been positively stellar. My devices rung a LONG time-- substantially longer than my Rayovac hybrids or older Energizer 2100's. I believe this is a testament to both the batteries' capacity and the charger's abilities...but, I'm not a pro on this stuff.
Though I love the Rayovacs, I also love the extended runtimes of the higher capacity bats.
Are any of the higher-cap bats holding up ok, or have people abandoned them?
Also, I don't use any super high drain devices. The worst is my camera...which is nothing compared to some of those super-incans.
I think the little Vanson is a fantastic charger. especially if you are an "average" user, and you want simplicity.
Almost forgot: Vanson has a newer charger called the Vanson V-2299. It looks similar to the Speedybox. I wonder what the difference is?