I have three T90s and used them all for about 8 years to cover the entire North American arc. For most people they appear to be a little tricky to setup, but I had no problems at all. In fact I found it trivial when adding additional LNBFs. The LNBF holders are designed for 4 degree spacing, but by doubling up LNBFs with grounding clamps, I was able to achieve 2 degree spacing. There were a number of threads/posts here in the past on the T90s, by others and me, that provide more details. Performance wise, both RimaNTSS and I measured better than 90 cm results on-axis, falling to about 90 cm-level +/- 10 degrees off axis. By 20 degrees off-axis, the performance is about the same as a 76 cm dish. I generally stuck to the center 20 degrees and found the sensitivity to be reasonable for Ku in North America. Compared to multisatellite reception on parabolic dishes, the T90s are consistent and reliable units.
If they made a 1.2 m toroid, I would be happier, but my T90s made much more sense than having a gaggle of dishes, one per bird. I suffer from very high winds, which makes motorized 1.2 m dishes impractical, and even fixed 0.9 and 1.2 m dishes flop around too much when the wind starts chugging. One storm even ripped apart a C-band HTH motor on which I mounted only a 1.2m offset. The T90s could care less about wind, and held lock even in the worst storms.
Recently I retired two of my T90s because I switched to two 2.6 m Birdviews for part of my Ku coverage. I needed extreme performance for a few cases where neither 1.2 nor 1.8 m offsets were enough. I still kept one of the T90s and it is working as well as ever.
