Help us with gutters

I was hoping that I could tap into the wonderful community of expertise and remodeling research to get some information about gutters. We currently have half round alumnium gutters on the house. We've been having a lot of problems with them (it's difficult to get to the ones on top for cleanout) and they aren't connected to the duplex neighbors' gutters, so water pours down the house where there are gaps. We had a roofer come out and look at the roof leaks, and asked him to assess the gutters (we were hoping that they could just be repaired). He said that would just be throwing good money after bad, and that we should consider the square boxy aluminum gutters instead of replacing with half round because it would be cheaper, they would work better, and the "half round hangers are really expensive and hard to find". I have no experience with any of this. We're going to get some more opinions and estimates, but any information you can provide would be helpful. Here are my main questions-
1. How do we know that we really need new gutters? How do we know that ours really can't be repaired?
2. How much more should we pay for the half round style? I'd really hate to go to the other type of gutter, the half round is more period-appropriate, and the other half of the duplex has half round, so I think that the boxy kind would look weird.
3. Does anyone have any opinion of those leaf guard systems? We have a gigantic long needled pine tree, and that's what's causing most of our clogs. It seems these systems work better for bigger leaves and that the smaller debris is what causes the problems anyway.
4. Are half round hangers "really expensive and hard to find"? I found them in a google search on the internet in about 5 seconds, and it copper too, but maybe this guy knows something that I don't.
5. The Mr. wants to price copper gutters, which would be beautiful, but I think too extravagant. Has anyone looked into this option? How much longer do they last than aluminum gutters?

Thanks for your help everyone.