I prefer the horseware, but that is just personal pref. I would pick the one with the most heavyweight outer. 600 will prob leak rather quickly. 1200 is masses better at keeping the rain out and will last much longer.
Don't know about the Horseware, but have a number of Masta rugs.
The Masta rugs have been pretty good on the whole; there was one that hasn't survived too well, but that might have been a Weathabeta, can't remember...
We tend to buy either Masta or Weathabeta as they fit our neds (a DWB, a lightweight cob, and a Welsh x).
Horseware without a doubt. I had a zing for the pony and it went on eBay within a week it didn't fit at all.
I only buy Horseware or bucas rugs these days (although did by a Pessoa last winter which so far is fab). As I kept buying cheap rubbish and replacing very quickly so its a false ecconomy. That said some of the Mark Todd rugs are brilliant too.
apparenky horseware are very good only have a masta stable rug not got any horseware as quite expensive-masta rug fits my pony with wide chest really nicely and a lovely rug