Solitude, generally speaking, the 7'10 will be easier to handle. All other things being equal, it will be more forgiving to cast. There are times when a 7' might serve you better (especially in brushy, boulder strewn, tiny little streams like we have in AZ). For the other times, the 7'10" will give you a little more reach for getting your fly into hard to reach pools, and/or around obstacles...a big plus when you can't wade in. Generally, a longer rod will roll cast better, especially with light lines. As far as forgiveness goes, the fly will be a little higher above your head, so you won't have to concentrate on keeping the loop as perfect (although that's always a desirable thing) to avoid tangles and the all-embarrassing fly self-hooking (don't laugh, this can happen a lot on tight streams when you're trying to avoid trees, etc)! IMO, the only real advantages of shorter rods is casting room. They do have their place...but generally, if you can have only one light line rod, 7 1/2 to 8' is the "right" size. Remember, these are my opinions and as you know, everyone has at least one!