I have used the HMEC 45 KA for about 2 years on Dash 8 turboprops and found it quite pleasing. It takes out a lot of noise, though you only notice that when you turn the ENC off.
Our company later introduced the -25 model which has a bigger earpiece (and is heavier) but cancels more noise due to it's closed-ear-design.
I found the -45 better engineered and lighter than the Telex Airman ANR although I don't really like the design of the earpieces. The foam cover is fixed and so, unlike the Telex Airman 750, you can't simply swap the covers when they're grimy.
On the original -45 the cord was quite short which made placing the ANR control box a bit awkward (I don't want it pinned to my shirt for several hours). I got a longer cord but be sure that's included in the price. Our distributor tried to charge me about 100 EUR for that.....