I am a 34 waist in jeans/shorts and loved my Bitihorn Flex1 (non convertible version) so much that i decided to give the convertible pants a try bc I wanted a blue or khaki pair and the regular Bitihorn Flex in blue were not in my size and there was no khaki option.
Even though I was a medium in the others, it was not even close. in these, i there is zero chance of a medium fitting more than a 32 waist - not a chance. After returning my first pair to get a Large I am very happy with the fit. I am 6'1 and 100% these have an extra inch or so of length that i don't need, so if you are taller than i am this may be helpful. In the traditional pair, in Medium, the length was perfect but would have been too short for someone taller than I am.
The features that convinced me to buy these (bc i am biased against convertible pants) are: 1) I love my traditional, Bitihorn Flex1, pants so much; and 2) you can take the pant leg off without taking off your shoes which is one of the reasons i have always hated convertible pants.
the other difference from the traditional bitihorn flex1 pants is that these have two cargo pockets (one on each leg) rather than just the one, and i think these cargo pockets are bigger, though i am not certain.
i will be keeping these and i will try to remember to update this review after i have used and washed them a few times.
I hope this was helpful.