840c and Canon pixma mp750

I have been using 'X-Print' inks from <999>
I have Hp Deskjet 950c + 840c and Canon pixma mp750.

999 inks have been getting worse & worse. Only very recent they sent
me just 1 correct (x-print) cartridge out of a full set of (5) for my
canon 750. It took 13 days of emails & phone calls. They finally
apologised (?) and want me to return the cartidges stating they will
re-imburse me the posting cost...? what a pathetic firm!

Anyway, I could do with some good advice on any other X-print
suppliers, or, other 'good quality' inks/suppliers please.

Thanks for any helpful advice...
Allen