I use now their products for some months and until now I am very satisfied. I like their multi-langauge options a lot and their scripts have a good price. The support is very fast, in most cases you get an answer in 15-30 min. They offer adjustments for a good but sometimes also a little too high price in our point of view. We made some changes, some by ourself and some with extern developers. (For example: We want to update the Responsive file manager which is integrated in the Simple CMS editor, which is an open source component with a commercial licence. Php Jabbers offer was 120$ for this, the developer who developed the responsive file manager (http://www.responsivefilemanager.com) updated it for us for 80€)
We always try to modify their scripts by ourselves, but if we once do not get the desired result, we always know that they will do it for us.
I also have to say that the support of phpJabbers also helped us solving a problem which we produced when we changed their scripts. So I only can recommend them.