We stayed at the Island Palms on our night of a late arrival and again on the night prior to an early morning departure from San Diego airport during a recent trip to visit relatives about an hour north of San Diego. I selected the Island Palms because it had good reviews, reasonable pricing and advertised that they offered an airport shuttle.
Our experience with the airport shuttle was not satisfactory. I had confirmed by email with someone from the hotel to call the hotel when we arrived. I called and they informed me that the shuttle driver called in sick but they offered to reimburse us for cab fare and did so that was fine. But on our outbound stay we inquired about the shuttle and they said it started at 7am. We had an 8am flight, so a 7am shuttle was cutting it too close so we ended up taking a taxi at our expense. I've never been to any hotel where the airport shuttle started so late - a bit ridiculous for many travelers.
I did use the shuttle during the day to go get the rental van and return it and it worked well for me then. (I was traveling with 3 relatives in their 80s so I didn't care for the chaos of getting and dropping off the rental van with them and their luggage in tow). In retrospect, I probably would have not worried about a property having a shuttle and planned to take taxis.
We did enjoy the location and strolling through the marina in the back and the park along San Diego harbor across the street. It was interesting to see a couple cruise ships enter and exit the harbor as well as some US Navy frigates and destroyers. We had breakfast in the restaurant and drinks/appetizers in the bar and in both cases it was good and fairly priced.