I've had T1Rs and Eagle F1 (GSD3)s previously, now using RE001 and wouldn't go back.
Grip is pretty similar in general (RE001 better when warm, T1R slightly better cold+wet), but the real kicker is sidewall strength - in that regard T1Rs are hopeless.
I found them too pressure sensitive, chewed out the shoulders pretty fast and were very susceptible to sidewall cuts on gravel, in fact I think they all died from punctures/cuts or uneven wear before the main tread wore out.
Eagle F1s had a more consistent feel than T1R but were still vulnerable to punctures, and like the T1R are extremely floaty on gravel - no surprise when they have a very similar tread pattern.
RE001 are better in every way except cold+wet grip as mentioned above, and there isn't much difference there either. I wouldn't mind trying the RE050 at some stage though, apparently they have similar performance but last longer.