Missing splits, missing dividends, double up splits, doubled up dividends, missing days of data, volume doesn't reflect all trades for a day, some optional corporate actions (eg. choose a cash dividend or a share dividend) both are included and adjusted in the price data, foreign currency dividends shown as USD dividends, fictional dividends, missing spinoffs, early history of the stock missing, crap security names, very late timing on corporate actions (sometimes months after the event and always 1 day delayed (pity the trader who puts on a stop to find there was a demerger event overnight). Really quite poor. The data is riddled with such errors.
Certainly the data is better than nothing and is affordable to newbies etc. Once they've earned their gold plated underpants they can afford to pay.
The data is from CSI so... Who would be better? I've seen some pretty bad errors but it's much better these days, I have a couple of sources to build a decent data set. From what I hear, paid providers have exactly the same issues.
Which part of it? The historical quotes page, csv data, real time quotes, fundamental data? I doubt it's all of it because then they might simply shut the website down.
I was hoping they would answer my email but alas...............no answer so far. Personally I use their historical data.