I have a TL4800p also. Rarely use it on High; too bright. Lasts forever.I borrowed a big blue TL4800 on a dive and liked the way it looks so I bought one. It was almost exactly 1/3 the price of my light monkey 20W canister light, which was their latest and greatest. That light head is very powerful but it has lots of back scatter and I just did not really enjoy diving with it. I don't care how many lumens its rated at, or how the circuitry works, all I care about is what does the light look like in the dives that I'm doing, and will it be reliable. We'll see about that last part, but I do have lots of friends using those lights in Mexico and they seem to be holding up ok. It's a $500 light that looks terrific in the Mexican caves. I bought an extra battery so I can do two 2 hour dives on full power, which I don't end up using that often anyways. Maybe this light will fall apart and I'll get pissed off about it, but until then, I'm liking it.
I'm thinking when I get tired of it or too old to dive anymore I'll donate it to tbone.