The Steyr LG110 has been around for well over 10 years, with the LG100 before it.
It has gone through a number of revisions but remains based on the same proven system that has won countless competitions, series, and titles.
You don't say what you want the rifle for, but as an HFT, FT gun the Steyr is a fantastic platform to develop with.
Like with any equipment there are people who love it, and others who don't.
Second hand they hold their value because they are an excellent piece of kit and for a lot of shooters trade up to them.
On here there is a huge knowledge base about them so issues can usually be sorted without too much aggravation.
You can control the power without having to return it to the manufacturer, and there are loads of customisation options such as stocks, air strippers, triggers etc.
The FTP900 is still (in my opinion) in a development stage. It's a great rifle but I do not know anyone who has owned one trouble free. This is not a dig, but an honest comment.
You can find threads on here that go much deeper into issues about both rifles and the best thing you could do is shoot both.
Air Arms are a fantastic company who support air gun shooters and the air gunning community, Steyr UK do very little, if anything and it can be hit or miss getting spares from them (through personal experience).
Both good guns..but I love my LG110 and would not change it for an FTP900.
MAD for it.
Steyr LG 110 Gary Cane, Leupold 2.5-8x36 TMR
Member of the UYK, UYB, UYC, UYH & UYE club.
I would like to agree with you....but then we would both be wrong !!