A majority of the 5 star reviews are from current ...

A majority of the 5 star reviews are from current employees- not actual customers (one even was my former account manager and another helped me with a technical issue).
I have been a customer of Guesttek and glad I was able to be done and rid of them. Their service is subpar, their support is laughable and the owner allows his pride to get in the way. When I asked to speak with the owner about my many frustrations regarding our account, I was pushed around for months until he agreed to speak with me- only via email (he refused to even give us a phone call). It was clear he did not care about our hotel, nor was interested in helping us. When I pointed this out, his response was to turn off our services out of spite. We were not in arrears, nor were we rude, he just didn t like to be held accountable.
Afterwards, it was brought to our attention by a former employee of Guesttek to check out their Glassdoor reviews, seems as though the owner is too busy with sexual harassment claims to bother helping out those that are paying customers.
I would strongly recommend current clients as well as potential clients look at their contracts, read the reviews of past employees and consider moving to a more reputable company.