It's certainly not an unreliable brand in itself - you're just as likely to get a failure as you are with the likes of Sapphire, XFX, MSI etc.
It's just that my experience of TUL's RMA service is poor - back in the days of the X800 I bought one of their X850XT PE cards from another retailer. It failed after a few months of use - not a problem, it happens - but the retailer had gone upwards. So I emailed TUL. No reply. Tried all their foreign email addresses but I never got a reply. So I gave up, and vowed never to get a product from them again. This stance softed a bit over the years as the bitterness subsided

, but still to this day I refuse to deal with them directly in the event of problems.
So seriously, in this case, you should be fine. Just don't buy a TUL card (Powercolor or VTX) from a company that doesn't deal with the RMA process itself. Because if you do get a failure, i'm pretty sure you won't be seeing a replacement or any money.