It all depends on your criteria for "The Best".
If you want a high revving tuneable engine, the maybe "the best" would be Japanese.
If you want cheap and fun and aren't worried about keeping it running long term, perhaps something French or Italian.
We're talking about Golfs though, so I think in some senses the Mk3 is the compromise car. It sits in between the modern looks, creature comforts and a bit of fun from a Mk4 and the classic looks, handling and great drive of a Mk2.
A Mk3 can be comfortable cruising on the motorway or sat in traffic on a hot day (with your aircon) but can still be fun when you find a windy B-road.
The Mk2 will be fun whenever you put your foot down, but you won't be quite so comfy in slow traffic, and it's unlikely you'll have aircon (very few Mk2 GTI's had it, though it was available).
As for cost, sure, you could buy something faster for less money, but it wouldn't be a VW. True a really good Mk2 is costing a bit more than an average Mk3, so you would get more (options and comfort) for your money. But then it's what do you actually want out of a car?
Do want something fast, or comfortable, or practical, or economical or cheap, or servicable? Or any combination of these.
I wanted something practical and cheap to insure, but I still wanted a Golf (cos I really missed having a VW while I deviated into something very cheap and italian), hence why I have a mk3 1.8 CL.