There are 4 tires that I will discuss, all in the same price range.
1) Good Year Silent Armor, your current tire. Great tire, long life, great on road and off road. Strikes a good balance. Higher priced than the rest in this list. Other than cost, no real down sides to this tire.
2) Nitto Grappler. A good tire, very popular in the budget rock crawler community, probably won't last the 7 years you got out of the Good Year. Does extremely well off road. Complaints are road noise and loosing 1-2 MPG.
3) Firestone Destinaition A/T. Another good tire, and a tire I currently run on my Toyota Tacoma. Good mix of off road terrian capabilities. Does equally well (or poorly depending on your view point) in mud/sand/rocks and excels at sand covered rocks with reduced tire pressure. However, while the tire is very good, Firestone customer service leaves a lot to be desired. Seriously, they suck at customer service.
4) General Grabber AT2. The second most expensive tire listed, around $20-50 more a tire than the rest, but also probably the best all around tire. Great life span, does very well on and off road, low road noise, doesn't hit your gas tank the way a lot of other A/T tires do. They are no mud terrain tire, but do reasonably well in mud though I am not sure you can compare the cement of island clay to mud! LOL!
If you can spend the extra $100 or so on a full set, I would go with your current tire. You have experience with how they work, and don't work, and the reviews seem extremely possative. (I have never owned them) If not, then the Grabber AT2's are my suggestion. Granted prices are different on the island (I was stationed in Oahu for three years and loved it!). After running the Firestone Destination A/T's for three years on my Taco, I am going back to Grabber AT2's, and that is what I will be putting on my newly acquired VX. It's the one tire I have owned that I never have to think or worry about.
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VX Status: Running Great! Build is coming along nicely...