I had a 2013 Ariel 142 for a few months. Ended up selling as I just never felt quite at home on it. Can’t comment on the 161 other than it used the same frame. I know they have gone 650b this year so I wonder if this is still the case. Not sure which year you are looking at so I can only comment on the 2013.
The frames come up small,I bought the largest one they had large 19 inch. I used to have an 18 inch Five (medium) and now a large Zesty (48cm) to give you some idea of sizing. I found it quite short in the top tube but maybe I have a long torso.
Overall the 142 was a nice bike to ride. Not light for a bike in that category/travel but I never felt like I was peddling a lump of granite around. I found it quite a playful bike, good for trail centres. I thought about the 162 for more travel, I too like blatting it down but the 142 was enough, not quite as stable as the Five I had before it but not far off. The forks let it down though.
In the few months I had it I noticed the paint chipped quite easily, it was taped up too.
One thing I found out was that on the 2013 ones at least you can’t run a coil shock oh and some people questioned the longevity of their Norglide linkage bushings.
I do like the look of the new ones but not at the RRP. I got the 142 for £1300 from Plush Hill Cycles. Not sure if they will do such a big price drop this year but worth keeping an eye out. Try one first though.