IMAP access VERY slow

IMAP access VERY slow

I am finding the IMAP performance (I use Outlook via a laptop and an iPhone to access Zoho Mail via IMAP) to be incredibly slow.  Is this a symptom of IMAP access still being in-test and can we expect the performance to improve any time soon?

I am looking at Zoho from a potential business use perspective but can't entertain it's use with the current performance issues.

Many thanks,
Craig.