These PI Select Thermals were my 1st pair of tights & as with any cycling apparel it was difficult to project my size (which can vary from M to L depending on brand) so I found these reviews very helpful.
I purchased these Tights for recreational road cycling. So far I've worn +100 miles & the comfort has been outstanding. The thin "thermal" fleece lining provides the added warmth I was looking for beyond standard tights. The material & stitching quality appear good & have held well up so far on long rides.
The fit is the tricky part. Several reviews indicate the need to order a size up but that depends on your body type as much as your measurements. I'm 5-9 (barefoot) 165lbs (birthday suit) 33" waist, 30" inseam with slender build & Medium was appropriate size for me. Fit is adequate - not great. Legs are little long & bunch at the bottom however this is solved by unzipping the ankle half way up which allows bottom cuff to slightly break over my shoes. More snug in hips than waist, thigh & calf feel tight & aren't as "flexible" as standard shorts but did not restrict my pedal stroke. That "compression" feel in my lower legs felt better the longer I rode. My guess is size M is ideal fit for someone 5-11 with 33/34 waist & medium build, any bigger & I'd go up to size L.
Tights have a drawstring in the waist which is unnecessary & should have a wider elastic grip there instead. For the price PI should include basic chamois padding (they don't) so I wore these Tights over my Castelli shorts (which ironically are size L but fit like 2nd skin) & that worked fine. After an hr I did have to pull up the back of Tights up a few times - this is likely due to the combo of my sweat/layering & Tights not "gripping" the slick exterior at the top of my shorts.
If you only ride occasionally in colder weather these Tights are a fair value. As with all performance cycling apparel you get what you pay for & I've come to expect nothing is cheap. I can justify spending far more on higher quality & better fitting shorts/jerseys/shoes because I wear them daily in Spring/Summer. For a few rides in late Fall or early Spring these Tights will do.