I do dressmaking plus P&Q, so I'm in both camps. I've always used rotary cutters for P&Q - never scissors - they aren't accurate enough, but I'm talking about using a rotary cutter with a purpose-made ruler for P&Q. For dressmaking I always used to use scissors until I thought "well, I love the rotary cutter for P&Q, so why not for dressmaking?". I tried using my 45mm rotary cutter on the long, straight pattern pieces - it was fine. I could even use a ruler for some parts. Then I used my 28mm rotary cutter for going round the curves, neckline, armscye, etc. That worked well too, so now I mostly use rotary cutters all the time, with the occasional use of scissors for very small, fiddly pieces.