I have been looking into mounts as I am in the process of upgrading what I have. I currently use a GP mount with a SS2000PC that is the light weight predecessor of the sphinx. The sphinx and starbook seem good but have their limitations compared to the SS2000. See
http://www.groupeastronomiespa.be/SSvsSB_V1.02.doc.pdf
I have just bought a new EQ6 (and hopefully it will arrive tomorrow) for ~$2000 as I needed the extra weight cpapbility over my GP mount.
The vixen mount will be better made than the EQ6 but I will wait and see.
You don't seem to need such a big mount with the 80mm refractors and if portability is important then the lighter mount would be the way to go.
PS. I will be selling my GP mount and SS2000 if I am happy with the EQ6 for much less than the $3000 of your budget. PM me if you are interested.