We have had three custom add-ons made by Ozzy & PainKiller, all reasonably priced.
Two were a bit smaller in scale, and the third was a more involved expansion of a previous add-on Ozzy had developed (with another XF software developer).
The first two were each quickly completed, with no tweaks needed.
The third required some debugging, which Ozzy & PK were great about, with the small bugs being handled quickly as we found them.
Highly recommended!