The T19 machines are almost indistinguishable from the (current) top of the line S19 machines. While they run 10% or 15% slower, the price is often around 20% lower, making this a decent entry point into mining if you're on a budget.
They're as robust & reliable as the S19 series, and will be a great starter rig or a great backup to have waiting in the wings to use while you pull a higher-hash-rate machine offline for cleaning.
If you have more electrical capacity than upfront capital, an entire farm of T19 machines would be a good choice. Once you're up and running you could upgrade to 100T+ machines as your cash flow permits. The quality of the T19 machines essentially guarantees their resalability.