What is your opinion on this one?
I'm worried about USDT running fractional and blowing up into everyone's faces, but Bitfinex I still sufficiently trust -- at least as far as you can trust crypto exchanges, which in general I wouldn't really recommend in the first place.
The accusations of Bitfinex pumping BTC using USDT I will believe once I see hard evidence. According to coinmarketcap Bitfinex currently only accounts for about 2.5% of USDT trading volume which makes Bitfinex pumping BTC using USDT rather unlikely. If they ever did, they stopped a long ago.