Does anyone knows the market share between plesk & ensim ?
I do know that plesk has more market share then ensin, but does anyone knows how share ensim does have ?

I don't think you can find exact numbers. But AFAIK cPanel is leading in overall. Plesk has some advantages over cPanel, like Windows version, built-in language packages etc. I think Plesk will come second if you look at global level.

PS: This should be posted in "Control Panels" forum ;)

Its difficult to say - overall plesk should be scoring more - I guess.