A bit like you, I saw a few in use and really liked the concept. Ended up with a 2nd hand Steyr Scout in 223 - justified as my summer muntjac stalking rifle, as well as one that was small and light enough for my daughter to use under guidance. Have to say that I am really chuffed with it.
It is certainly choosy about ammo. Mine has a relatively tight twist rate, so suits the heavier bullets, but be careful as twist rates vary even within calibres - The Steyr Scout rifle typically has a 1:12 inch twist rate for the .308 calibre. Some limited runs of .308 Scouts may have a 1:10 inch twist rate for improved performance with heavier bullets. Other calibres like 7mm-08 and .243 have a 1:10 inch twist, while .223 has a 1:9 inch twist (from t'internet!) .
Previous owner swore by Hornady V max 55 grain, but I could not get it to group that well with a similar bullet (Norma), plus I wanted something suitable for deer rather than vermin. Swapped to Sako Gamehead 55 grain and was able to consistently get 1" groups off sticks at 100m. It is light, handy, easy to put on sticks, and short enough (even with a moderator on) not to catch on branches when sneaking through woodland.
If you get an older model then you may need to replace the magazines as the earlier ones had a feed issue. I found mine would sometimes jam when feeding the Norma, but works perfectly with the Sako. What such a light rifle is like to use in a bigger calibre I am not sure, but in 223 it is great. It is a bit of a Marmite rifle - you will either love it or hate it.
Good luck.