There is noticeable recoil, but only if you're able to apply a large amount of stillness to your position.
If the rifle has a poor lock-time, and/or a particularly long barrel you may experience it knock you a few millimetres of target, and subsequently miss.

Things like being un-regulated and having a blank muzzle would probably make a difference, but given I generally avoid un-regged rifles for target work I've never spent any particular time assessing these theory's.

Steyr fit stabilizers for a reason, and I'd be interested to try out one of the LG100 High Powers, which did not have one fitted and compare.
If you want to experience dreadful jetting, try a regulated Daystate MK3 .177. It might have been to do with the sleeved brake fitted to the FTR as standard, but the jump was exceptionally awful.