I think this is the right time to move on and you should go to Man Utd. I know this kind of 'generous' board can be very frustrating. But remember the game may become too easy at United I'd pack my suitcase and leave London.
I think u should stay at palace,it may take time to build a squad of super stars but I think u may just regret leaving.
Take the Man United job, who would want to stay at Palace anyway
Do whatever you will find most enjoyable mate
I think you should remain at Palace. You've done well with the little you have so far. Hopefully someone will come an takeover the club and provide you with the finances you need; just like in my managerial story. Keep doing what you've been doing. And by the way, it's just your 3rd year at Palace, remember??? It's a 5 year plan