Hilti still make some very good tools...and some junk.
I use their hammers on a regular basis, esp. lately with daily use for the last month or so and conclude as follows: their smaller hammers, such as the TE6 are gutless & slow compared to their competitors (Bosch). However their SDS Max drills are capable, hard working & reliable.
A colleague has had a very heavy 18v cordless Hilti drill in heavy, daily use for about four years now and, apart from a chuck replacement and less "charge life" in the batteries, has performed flawlessly. Needless to say, we're all impressed!
After years of frustration using 18v cordless saws from a variety of manufacturers, I've now moved to 36v myself. I believe that for Aust. hardwoods, and ripping softwood, anything less is inadequate, irrespective of brand. 36v saws typically have an output of about 600w, still only barely adequate for some jobs, but about the max. it's possible to safely wield using current technology.
I believe that some tools (circ. saws, SDS hammers, and 5" grinders) require at least 36v worth of power to perform efficiently. Other cordless tools (drills, hammer drills, recipro. saws etc.) can perform satisfactorily with less: I personally hate using my 36v hammer drill (way too heavy, large in the hand and unwieldy). 18v seems to be the current optimum size/weight/power/charge life compromise for these latter tool types.