As mentioned, it really comes down to what your throwing. It makes a huge difference if it's double 10's bladed bucktails or bulldawgs.
I'd say, save your mioney and buy a Shimano Tranx 300/400, Abu Revo Toro Beast, Daiwa Lexa 400 or a Shimano Calcutta D. Buy used if you have to. These reels should last a long time. The new Abu Ambassadeur Beast looks awesome too.
That being said, a lot of people do start out with the Ambassadeur reels. It's probably not a bad idea if you aren't going to be targeting musky all the time. The nice thing about the 6500 is that it has a clicker for trolling, but the 5500 does not. I don't know about the newer ones. Still, if you look around you might be bale to get a much better used reel for not much more money. Even if you go with the Ambassadeur, I got mine used from eBay for a good price.