I do like the cloth, such as stits, but I like fiberglass because it gets rock hard and it can get banged around without punching a hole in it like cloth.
I know this thread is about cloth but heres how I fill the weave when i fiberglass:
1: lay cloth down, saturate in resin, use a credit card (or similiar) and push all the excess resin out, wipe up, and wait till it cures
3: Put another layer of JUST resin, push excess out with credit card
5: repeate with adding resin and sanding till weave is filled
It is a more time consuming process, but its much easier to fill the weave putting more layers of only resin on than bondo like some people do, and gives a good surface to sand.
So to end it, I think it depends on the airplane. A warbird I would fiberglass for sure, but a sport plane and similiar, I would use stits cloth.