They're accurate enough. Certain wording choices I think are odd, but not much can be done with the DVD format. Definitely get them.

From what I've seen it's pretty spot on. Some of the wording is different if you've seen the fan subs but it gets the point across. I usually point to an example from the Tsubasa OVA Tokyo Revelation that you can word the same phrase several different ways. The example being one sub group will phrase a line "Without fail" while another will say "no matter the price" meanwhile the official dub will have it as "at any cost."

Same line different version but both are still accurate and the Zyu and Dai dvds are much the same. Most you'll find is the occasional slip up here and there, but that's to be expected with foreign films in a different language. You wanna see some really bad translations, read the Duwang version of Part Four of Jojo's Bizzare Adventure and have yourself a good laugh at "I AM THE FUCKING STRONG!!"

From what I've read, the only real inconsistent spot was Byakko Shinken's name in the Dairanger subs.