The quality varies a lot from series to series. Personally, I think the Crunchyroll subs for recent series (Adventure: and Ghost Game) are very good. In particular, I really like some of the translation choices Ghost Game makes for things like "saikyou" (lit. "strongest", translated as "champion") and "kansuto" (lit. "stat cap", translated as "integer overflow"). The Xros Wars and Appmon subs on Crunchyroll also seem to be very good.

Despite my complaint about Adventure tri. leaving "jikochuu" untranslated, I think the subs are good for the most part. They're a little vaguely phrased, but I think that was probably inevitable; Japanese is a "high-context" language that normally requires translators to rely heavily on context to fill things in, but Adventure tri.'s context itself is often vaguely written (and sometimes even contradictory) even in Japanese, and I don't think there's much that could have been done otherwise. At least, I don't remember seeing any lines in the subs that made me feel they were semantically mistranslated. On the other hand, LAST EVOLUTION Kizuna's subs are awful; they might look like they read okay on first glance, but there's misheard lines and lines mistranslated to mean the opposite of what they're supposed to, and I don't think the translator was familiar enough with Adventure (or Adventure 02) to pick up on the references they were making. To make things worse, the official subs for the new Adventure 02 movie's first trailer shows signs of the same kind of sloppiness (it translates "gate" as "door" even though "gate" is an important story and lore term in Adventure 02), so I'm already not optimistic.

From what I saw of the Adventure subs on Crunchyroll, I think they're very well-done; a lot of thought seems to have been put into the jokes, wordplay, and things like Tentomon's Kansai dialect. The (current version of the) Adventure 02 subs on Crunchyroll are more of a mixed bag; they seem to be a re-edited version of the really awful one that used to be on there a long time ago, and there's a lot of remnants of the old version that don't seem to have been addressed (personally, I think it would have been better to just redo the entire thing from scratch instead of trying to salvage the old one). The inconsistent terminology was smoothed out and some of the lines have really good and punchy translations, but there are still some lines that feel shaky, don't have enough attention to character voice, or are even still mistranslated. I think the best comparison would be the Cyber Sleuth/Hacker's Memory localization, which also flips between really well-translated lines and really conspicuously bad ones.

To put it briefly, I think they're generally definitely better than the infamously disastrous Tamers subs that used to be on Hulu, but there's still a lot that needs to be improved. Of course, this is all just my personal opinion.