Which browser is best for Zoho sheets?

Which browser is best for Zoho sheets?

I've been using zoho sheets for a few months now and the past few weeks, it has appeared much less stable.  Sometimes my document won't load after I select it.  Other times, it locks up every few minutes as I'm trying to enter my data.  I'm on Win 7 and have tried many browsers including Chrome, Opera, IE, Firefox.  IE seems to be the most stable at the moment.  I'm not sure what else to do.  Any suggestions?  I only have one file in sheets.