Personally use Tether USD. You want to compare to something less volatile otherwise you can lose with fluctuation.
I actually don't like Tether at all.
at first sight it seems the most convenient but when you pay more attention to its details you can clearly see that using USDT is adding an additional risk to your investment. it is not decentralized like cryptocurrencies so you can't really use it freely, also it is not promised to stay at $1 and a simple swing can mean a huge loss on your part which nobody covers or cares. for example we saw the big dip that it had when bitfinex was hacked last year.
This. Tether has been very shady eversince. The thing is, tether is not actually backed by anything. It's completely stated on Tether's TOS:
"There is no contractual right or other right or legal claim against us to redeem or exchange your Tethers for money.
We do not guarantee any right of redemption or exchange of Tethers by us for money."
Also, like last week, $25,000,000 worth of tethers are generated. They're simply just creating tether out of thin air. Sketchy af. I personally only use tether(USDT) when making quick trades. I'm definitely not keeping them for more than a few days.
Here's an interesting read on Tether(USDT):
https://hackernoon.com/the-curious-tale-of-tethers-6b0031eead87