On the contrary, I think, from a sailing and exploring perspective, the SXM sailing grounds are more adventurous than the BVI. We rotate between the BVI, the Grenadines and SXM. We're doing our fourth trip to SXM in two weeks.
We usually do couples trips or two families and all those that have sailed with us give SXM-AXA-SBH rave reviews. Its a different trip than the BVI and you'll really love it if you and your newbies are foodies. We generally dine ashore every night.
Our usual route is Oyster Pond>Grand Case>Road Bay>Crocus Bay>Baie Columbier>Gustavia (2 nights)>Oyster Pond.
Grand Case is full of great restaurants. take your pick.
At Road Bay taxi to East Shoal Bay or Meads Bay and enjoy a beach that rivals any on Anegada. There are a number of great places for dinner on AXA, too.
Crocus Bay is a quiet bay with snorkeling nearby and a good restaurant ashore.
From Crocus sail around the east end of AXA thru the cut and all the way to St Barts. This is a lively open ocean sail. Stop for lunch at Ille Fourche or Baie Columbier (can overnight in Columbier).
At Gustavia rent a car and explore the island, hit one of the beach restaurants for lunch and dinner at one of the great restaurants in Gustavia. We usually hit Saline or Gouverneur beach for a half a day, too.
Then we usually motor sail back to Oyster Pond.
I think of the BVI as laid back and funky beach bars and SXM-AXA-SBH as a more sophisticated villages with great restaurants. All with beautiful islands, trade winds and water.
Are your newbies sailors or just new to the BVI? If they're new to sailing perhaps the BVI is the better choice.
PM me if you decide to go to SXM and I can give you more specifics.