Well, obviously Jim and I differ on this one, so let me clarify the points I was making. But first, if you want to stay on the mainland near Marathon you will have to exchange into the Golden Coast Holiday Club, not the Sun Beach Holiday Club (it is on Rhodes). The Golden Coast Holiday Club units are clean but austere. For us, the major fault with the resort was we did not feel the location was convenient to Athens. We took a bus to the city, then took the subway, so it is doable, and we knew this when booking. But, as I said -- if I really wanted to see the sights of Athens I would reserve a hotel room in Athens next time and spend less time commuting. Jim is right about the day trips though, we did a day trip to Delphi from the resort and it was very good. So, the decision is commuting versus convenience.
As for driving - we did (and I'm still posting!). I quickly learned that in Greece a two-lane road is really a four-lane road because slower drivers are expected to pull over to let faster drivers by (the shoulders are all paved on the major roads). I did this regularly and often stopped to enjoy the scenery, which is very beautiful on Crete. Jim's point about the high number of traffic fatalities may be right, based on the number of roadside shrines we saw. There are aggressive drivers (they're everywhere) and some of the roads through the mountains are narrow and the cliffs can be intimidating, so in both cases I just took my time and drove defensively. So, IMHO, if you want to really explore Crete, rural villages for example, I believe you will have to drive.
Carl