Having them both, here is my oppinion & why-
The slx falls between two sizes of facelift poles. Slx is an actual 25ft in extended length, facelift 24ft (actual 21ft) & facelift 30ft (actual 27ft) & there is a big difference in useability between these two f/l poles lengths.
Clamps- f/l clamps are superb & very easy to use BUT the downside to them is that each clamp adds approx 100mm to the closed length of the pole. The slx clamps are also superb once fine tuned (very easy process with an allen key) but do require more getting used to. However, the slx clamps add very little to the closed length of the pole & i would suggest are stronger than the facelift clamps although my f/l clamps have never failed in approx 20 months of very hard use & abuse.
Slx Vs 21ft facelift=
Weight wise there is not much in it, nothing worth considering. Rigidity, again, nothing much in it but i feel the slx is a tad more rigid in use.
Useability- both very useable poles but the slx wins on it's shorter closed length & extra 4 feet in extended length. Also the slx, for me anyway, with a plastic angle neck + swivel can do every bottom window on my round where as the f/l is a tad too long for some but can do the majority.
Slx Vs 27ft facelift=
Weight wise there is now a very noticeable difference, the slx is much lighter. Rigidity, the slx is also quite a lot more rigid now.
Useability- Here the slx wins hands down, the closed f/l is far too long for bottom windows & is not IMO an all day pole. The slx still has the same closed length but the f/l is two feet longer- extended. There is a very big difference in useability between these two poles with the slx blowing the f/l into the weeds!
The extra (actual) two feet that the f/l has, no where near out-weighs all the extra benefits of the slx.
Summary & considerations-
Both superb poles, top quality, both very well built & robust, but for me the slx wins hands down. The slx is a pole of actual 25ft which is a superb, very useable length. It's very well balanced, has a very short closed length, even when fully closed it balances perfectly for bottom windows & IS useable all day long from ground floor up to 29 ish feet! Add to that, it's very light, rigid & cheaper than the facelift! On the side of the facelift though is the ability to go higher by just adding extra sections, although i would imagine gardiners are probably developing extra sections for the slx?
Also i don't look after my poles, i throw them about & hardly ever clean them, they are my workhorse. I've had the facelift for approx 20 months & the slx since it's release. Both have stood up so far to daily hard use & abuse although i only use the facelift now for anything above 30ft (as mine is the 44ft carbon). I stated that the slx is cheaper than the facelift BUT i havent recently checked facelift's prices, so i'm assuming they havent reduced their prices.
This is my considered, honest oppinion. hope it helps.
Tony