Use search for my detailed T800 vs S8F comparison.
Before T800 I had IT04 and I´m still missing that lovely DD bass, but it didn´t fit my ear that well and I´ve found the treble to be unnatural (depends on insertion depth tho, so that could have been the reason for me not liking the treble). T800 has more treble sparkle and extension for sure, for my ear, not sibilant at all, some hear it a bit sibilant though (there is possibility of taming the treble with some kind of diy filter, or swap the knowles damper for stronger one, which will however dampen mailny upper mid peak). T800 is a detail monster which can be tastefully tuned to your preferences by choosing the right source, cable, tip and damper
Recently I compared it even to Moondrop S8 which while being more refined product showed me how well T800 performs for the price. price/performance of it is insane.
I heard FH7 briefly and it was a big disappointment for me, after liking FH5, I probably expected a lot more from them.. But the sound was just too sibilant and uneven for me. This is just after maybe 30min of listening to them, so take it with a grain of salt.