Yes, I would value an A3000T over an A4000 anyday!
The only benefit I see inthe A4000 is the AGA.
The A3000 is a much better design and can run just as fast as the A4000. The A3000 also have much faster ram. If I was to get an A4000, it would eb the A4000T and not the desktop.
It is not hard to be faster than an A4000. I have an 040 board for the A2000 toaster and it is 10% faster that a stock 4000 which uses the 3640 just as the A3000T.
The AA3000 ot the A3000+ should have been the next Amiga and not the A4000.