The only bug I encountered was when I was running around in the fields and saw a chest floating a bit above the ground. Tried to get to it but I hit an invisible wall. Suddenly the ruins of a half burned building popped up around it. Basically that house failed to load for about half a minute. But hey, at least I knew there was a chest in there! Might have just run past it if it wasn't for that bug.
Apart from that, surprisingly solid game, apart from some framerate issues. Nothing that ruins the game for me though, and I'm playing on WiiU.
Any tips for fighting those giant dragons?
Also, whats the best way to get rupees? Just mine?
You don't really 'fight' those dragons (there's an exception but that might be a spoiler). They're not evil. You can shoot them with an arrow to get a special item, but you can do that only once per cycle. You can't kill them.
Money: sell meals, some go for 150, 200 rupees. Some NPC's give a lot of money for certain materials - there's a guy that gives you 100 rupees for a certain type of meat for example, and some NPC's trade certain things for diamonds (although you might want to hold on to those instead of selling them). You can also sell some materials, but know that almost everything is useful for upgrades later. Try to sell stuff that's worth something but not too much effort to get more of if you need it later.