I'm still a huge newbie with teaware (always more to learn!).. but here are my
opinions
I've been in search of 'high-end' gaiwans for a while, and so far I've found that my preference seems to be hand painted gaiwans from Jingdezhen, which from my understanding, the majority advertised as being such are still mass-produced, but are often still more pleasant to use than some handmade ones.. Does that make sense?
I've got a few hand-made gaiwans that are lovely but seem thicker and a little clumsy to use compared to the lovely thin porcelain of a molded gaiwan, then again, a lot of people would prefer this!
My favourite type of gaiwan so far is the beautiful one I got from MTR, but apparently no news on new stock for those

I want to buy another.. I've got some ones which have cost me more, but the MTR one has been a solid favourite!
Edit: Ok so that was mostly rambling about stuff I like as opposed to anything helpful lol sorry!!