There is obviously a lot of misinformation out there. Most of it is well-intentioned, but it is still misinformation. I had a problem last year, described below, when I tried to add a newly-purchased Shell Island week to my HGVC account. The email from Lisa at Shell Island, quoted in this string, is accurate. People can purchase Shell Island weeks and have them added to their HGVC accounts.
I have been an HGVC owner who also owns at Shell Island since 2001. I bought before Hilton was no longer the manager, and I have purchased several times since, including in 2018. I have always been able to add my newly-purchased weeks to my HGVC account. The process is the same as the process at any of the SW Florida affiliates. HGVC has a form to be filled out and a fee to pay for each week added. HGVC requires that the form be sent in with the fee and a copy of the recorded deed. I assume that if you are not already a HGVC owner, you will also have to fill out an application and pay the enrollment fee for membership as well.
I will also say, however, that last year (2018) when I purchased another week, I called HGVC and the people didn't know what to say. I was promised a call back and did not receive it. I called again, was put on hold, and then told that HGVC was not permitting any additional Shell Island weeks to be added while the red tide was in effect. Later I called Hilton's sales office on Sanibel Island and was told I could not add my week to my HGVC account because it wasn't permitted any more. Eventually I just called Shell Island, was told it could be done, and that they would pave the way for me. They took care of it immediately and I shortly thereafter had the form to fill out and the address for where to send it. I even know the name of the person at HGVC who processes the forms and will give it out if anyone contacts me privately. She has worked at HGVC for many years and has been processing those applications all of that time.
To the persons considering purchasing either at Tortuga or Shell Island: I feel the same about the maintenance fees. In addition, my wife likes the beach at Shell Island better, because she is a committed sea shell collector, and she believes the beach there (closer to the lighthouse) is better for shell hunting. I don't know if that is correct or not, but if that is what she thinks, no one is going to talk her out of it. I have been told by another friend that anywhere on Sanibel is a good place to hunt for shells.
Tortuga has some nice amenities also, however, including larger units and a larger lanai. For older people, Shell Island's units are each all on one floor and there are elevators. Tortuga's weeks are Friday - Friday, and Shell Island's are Saturday - Saturday. That makes a difference to people who own a week at one resort and want to add the next or previous week so that they have two or more weeks in a row (people at the HGVC affiliate resorts in Florida basically trade very little, so it is next to impossible to trade for one of these weeks via HGVC, RCI, or II). People who own Saturday-Saturday weeks don't like purchasing Friday-Friday weeks, and vice versa. The resorts are landscaped differently, although both are nice. Tortuga has a poolside bar and grill, whereas Shell Island does not. I'm sure there are other differences as well.
I was sorry to see Hilton go as manager of Shell island in 2009. We had a bad board of directors at the time. Most of them are gone now. Kenoyer Real Estate has been the manager since then and in my opinion is as good a manager as any could be. It has certainly consistently hired good people to work at the resort.
I have found that exchanging a Shell Island week for HGVC points is a little more complicated than turning in my other HGVC weeks at other HGVC resorts. I have to contact Shell Island and it then arranges with Hilton for the week to be deposited and for HGVC to deposit points into my account. In addition, Kenoyer's own policy requires that present year maintenance fees be paid (that is no surprise) and that a portion of the following year's maintenance fees be paid if the week I'm depositing into HGVC is a week from the following year. This is in contrast to my other HGVC-affiliated weeks at other resorts, where I just go into my HGVC account online and cancel the reservation online. Canceling at Shell Island and having the points deposited can easily take a full day or even a couple of days. I believe the requirement that I make a deposit toward the next year's maintenance fees is so that I won't refuse to pay the fees next year if I trade away my week this year. I suspect Kenoyer must have run into problems with people in this regard, so it requires the deposit. I don't mind making the deposit, because I would owe it at some point anyway.
All of the Florida HGVC affiliates (this may not include Sunset Cove) have an advantage in that an owner can be a member of HGVC, RCI, II, or any combination of these memberships. In my case, I'm a member of HGVC and II. I could have a separate RCI membership, but I just make do with the RCI membership included in my HGVC membership. I generally don't trade with RCI or II because I much prefer the quality of HGVC units, the ease and flexibility of use, and the service over RCI and II.
We definitely want our home resort to be in Sanibel and want to trade in HGVC. We are also considering Tortuga Beach Club, but the O&M annual fees at Shell Island are almost $500 less. Neither resort has a match for us yet, but we want to be prepared if one comes available. If trading in HGVC is the exact same at Shell Island as Tortuga we would much prefer there because of the heavily reduced O&M.