After being here for a good number of years I have had all the main ISP's at some time or another and can categorically state that they all work fine when used within the Thai domestic network. However it's a different story when you need international connections for streaming, torrenting etc as all ISP's have to pay CAT for international bandwith usage, and as they all may work fine initially, after time you will have problems with buffering and freezing due to the ISP throttling your international bandwith I am currently having this problem with current provider from 7pm to 11.30pm every day (peak international demand) . I have 500/500 package and when I do WIFI speed test (using nPerf) to server in Pattaya I get ping 5.5ms and average 250/200Mb/s, when I do speed test to London server I get ping around 270ms and average 44/168Mb/s, which proves they are constantly throttling download speed but not upload. However when i do speed test to same London server when experiencing buffering/freezing between 7pm and 11.30pm my results drop considerably to between 3 and 9 Mb/s download, 35 and 70 Mb/s upload with ping anywhere between 420ms and 780ms.
I have spoken to them about this issue and they actually admitted that yes they throttle international connections when they see a heavy download demand being used for streaming services, as apparently this has a knock-on effect with the domestic internet network, not sure how and they couldn't explain it either. Their final statement was that upgrading package will not make any difference as speed figures quoted are guaranteed only for domestic internet market and no guarantees for DL/UL speeds for international connections.
Solution - get a VPN, problem solved.