In my opinion competition is always good for customers. I am glad WHSuite is in the market. Currently we are using WHMCS too and also own a CE license. However being aware of other software in the market and following the latest trends is a necessity in my opinion.
I have also seen the LET thread about WHSuite. Initial comments are not very positive. However, one of those comments come from a leading Blesta reseller, so I am a little doubtful about those comments. May be the best thing is to download the trial and test it on a local environent.