Yes, it's a comparative donkey..... still, probably OK for most trading.
When people ask, I suggest nothing slower than the W3530 CPU.
Sometimes going "too cheap" just isn't a good idea.
Where paying $519 for that T3500 might make sense would be where you had your hands on a much faster [compatible, of course] CPU.... at the right price... you could swap out.
As a rule of thumb, I consider the proper cost of a workstation machine to be about $600 + CPU + RAM (when RAM was more costly).... and of course some of Dell's deals are MUCH better than that.