Hey Marlow,
I recently picked up a new solo L and love it. I was in the same position, trying to choose between the Ex and the Reg. I ended up going w/the regular for a couple of reasons.
1) I like to carry a breakdown paddle, the hatch doesn't allow for that.
2) The possibility of leaking over time is an issue. I tend to keep and use my boats over many years and the chance that a leak could develop over time is a reality.
3) having a hatch blow in a rapid, or the bungee snag on something has its concerns too.
4) You can pack as much if not more gear in drybags in the regular boat.
The new modle has great outfitting and some forward thinking in the realm of ibeams. I demoed a 05 and the thigh hooks were cheesy, they have overcome that issue with a new set-up.
Whatever choice you make, you will be happy with the boat.
Tobias