I am not sure I get this comparison, two different price points. GCBC is about 50% more than Divi or most other TS type places, so if you were to add 50% to GCBC would you compare to La Samanna?
Take the price you paid for a TS week divide it into cost per week, add the MF, the added charges resort bills for who knows what---it's listed on bill as "resort fee" and taxes. Add in daily maid service fee, fee for extra persons using unit, fee if you ate breakfast there and fees for water sports then compare to rates at GCBC and it's a slight difference not 50% more.
Plus what you're getting at GCBC is of higher quality, from unit furniture & appointments to beach chairs, towels and service.
As to difference to La Samana, I haven't stayed there so I can't comment.
Now if you want to compare to BVS then BVS wins hands down.
I like and have stayed at both, really like GCBC for a few extra nights and we have enjoyed staying at Divi for weeks.
As for friendly staff, of all the places we have stayed the most friendly staff would have to go to Sea Palace. Don't really want to stay there again but from front desk to maids they were the best. Best maids overall I would have to give to The Towers, and best front desk would probably have to go to Les Balcons many years ago but most have been pleasant. Best beach service at a resort was certainly GCBC, but we rarely stay at the resort for the day but if at GCBC we would more often.
My two bits. GO ZAGS!!!!