Eh, those are a very mixed bag. I'll take a Mauler all day long. Never had the original, but I always wanted one. I wouldn't mind a Snowcat, but there are just several ground vehicles I would prefer first.
HAVOC.... is the dumbest Joe vehicle this side the Tank Car.
You look at '85: Mauler, Snowcat, AWE Striker, Bridge Layer... all useful, *mostly* practical military vehicles.
You look at '86: HAVOC, Triple-T, and Recon Sled.... the designers came to the conclusion that all ground vehicles must be based on the concept of a zero-turn lawnmower, driving while on your stomach, or in the Havoc's case, both. WTF, Mattel. Who even drives it? The guy sitting in the exposed lawn chair on top (while also manning the guns that can't pivot laterally), or one of the prone people in the glass coffin up front?
I'm confident it was the same designer who just went in a rogue direction that year, and it was too late to change by the time someone realized the guy was insane. So aside from every '86 character being a replacement for a classic, the vehicles took a turn toward the absurd, and IMO, the franchise went downhill from there. Not to say that I hate everything after '85, but that it just got "spotty", whereas everything in the first few years was pretty much awesome across the board.
But I would not back a Haslab HAVOC, not a chance in hell. I owned the original, and it was the vehicle always destroyed in battle first (along with its inhabitants), and then the good characters would use the wreckage for cover.
Sure, it had several play features, and the little flying canoe was fun if you didn't think about it too hard. But the entire vehicle was a death trap. It made my 11yo self question what they were thinking, where before, I just took it on faith that the designs were solid from a tactical and operational standpoint.
And I was today years old before I ever saw a Joe "Hammer". Zero chance I give that a second look.