Baader Zeiss T2. Works perfectly with the 30mm UFF without any vignetting.
It's already been said, but the biggest difference will be seen at higher powers. It's much easier to see faint features on Jupiter for example than with a mirror diagonal. I have the Baader mirror which is excellent but this prism just takes the next step upwards. I still use the mirror for doubles as I don't see a difference, plus the mirror 2" can take my 42mm LVW.
Prior to this I had the Tak prism and the differences between the two visually are slight, however, the Baader is far easier to use with the clicklock and takes 2" eyepieces whereas the Tak was 1.25" only.
One thing to note is the shorter light path. It's shown here with the 35mm extension but doesn't come to focus with that. I have to use the Tak 80mm which came with the scope.