Well, are you confuzed yet?
Yes, it was a dizzying array of advice but not much about the OP's question.
We are all about local flavor....
Local flavor is a funny word. I have written at length about what I decry as the lack of real honest "island culture" available to the tourist on the Bay Islands. This has caused much hue and cry among local merchants who haunt this forum (but like BKPIX says above....)
About the most island flavor that there is might be found in a couple of very different forms between the two islands that you mention, Utila and Roatan.
On
Roatan, your best bet to get an "island vibe" is West End where you will be with a generally younger and more backpacker crowd, although that group has decidedly moved on to Utila. On the West End, you will find many guest houses and day-dive ops that are staffed by young folks who you will likely meet at night at one of the local watering holes. Warning: There is already even some sporadic neon signage! The buildings are a clever melange of tropic castaway chic and Central American engineering. Someday, like Cayman Kai, a bulldozer will come through and pave the place, running the Anglo temporary transplants of this attractive
Tropical Renaissance Fair lifestyle out of town.
On
Utila, you have this same net effect but miniaturized and highly concentrated and absolutely devoid (so far) of Cruise Ship Pod People. Think Cayman 1950 (only with wireless). Different than Roatan- nor will you see the line of Guatemalan import shacks or semi-contrived tropical shack style bars.
Either way, see it now, it won't last long on either island.
If you want the fantasy portrayal of "Island Flavor", it depends on which book you are reading.
MaragarittaVille? Try the west End of Roatan.
Robinson Crusoe with maximum diving (and shore diving)? RobinT has it right with CoCoView.
Early Caribbean atmosphere http://en.wikipedia.org/wiki/Don't_Stop_the_Carnival and lack of crowds? Utila.
If you want a Rastafarian in dreadlocks playing a steel drum, you got the wrong historical heritage for the real-estate in question. The controlling landowners are very English speaking second Cousins to Cayman Islanders. The bulk of the populace are lower class working folks including Garifuna, Caribe and "Spaniards" (mainland transplant workers), none of which you are likely to have familial access to. The real (current) Bay Islands culture is MTV, hiphop and a blending of subculture affectations that most North American visiting divers can not relate to very well.
The Caribbean is largely a Petri Dish of recently introduced cultures. Add in the advent of availability of American Pop Culture and all bets are off. In Bonaire, very few divers ever hear anyone speak the local Papiamento language, yet many divers who visit there walk away thinking they have Bonaire all figured out.
Local flavor? Maybe.
Island culture? Not really.
But to paraphrase BKPix....
Like they say: opinions are like a*%#@$*s, everybody has one; so that was mine.
Now, for some mathematics....
...we would like to dive a minimum of 2/day. If not more. Perhaps with shore diving as well.
The best and arguably only real
shore dive on
Roatan is the one that is shared by CCV and FIBR. It is essentially a doable dive 24/7/365 and the parade of divers doing it (certainly as compared to any other theoretical shore dives on Roatan) goes a long way to prove that.
Not real sure about
Shore Diving Utila in that comparative way. Some folks are claiming shore dive access there, but I would like to see the satellite imagery map for that one. I've not yet been wowed.
Two a day is a reachable goal at any dive op anywhere in the Bay Islands.
At some dive ops, that is the likely maximum.
Therein lies the crux of the biscuit. DiverSteve made a reference to that issue. In Roatan, at the day-dive ops, getting three a day is a dead-run hustle. As he mentions, you can make this more do-able if you go back and forth between nearby West End day-dive ops, working their boat departure schedules in a mix and match way. Night dives,
if they have enough divers, are once a week.
This scheduling of dives is very typical of any dive operation focused on Euro-Asian visiting divers. Since the British gave birth to West End Roatan diving, that's how their day got laid out. Factor in the size of their boats and ability to carry multiple tanks, the catering to Cruise Ship guests on a schedule- that's why it is laid out the way it is.
If you want 3 or 4 a day plus an easy night dive every night, your choices are much more limited. See RobinT's advice above.
You have to decide really and assuredly how much diving you want in a day. That will make the decision for you on Roatan. On Utila, the dive-ops are on a fairly equal footing and schedule, so this is not as much of an issue.