Damian -
The 4-section tripod is likely to have a skinnier lower leg section, which will probably flex a bit under load. So if you're planning to put something heavy on it, you might want to give it a try in-store to be sure. Stability and vibration dampening can be enhanced by using the weight hook that is included with the tripod. Hanging a bag on it can make a world of difference (assuming you aren't overloading the tripod of course). Be careful when raising the centre column... vibration resistance drops dramatically when it is extended. I have a small 4-section carbon fibre tripod which I use for backpacking and I like it a lot. It does flex with load but it stays still, which is what you want of course. So unless you see some obvious mechanical compromises with the 4-section unit (cheaper leg locks or something like that), then I'd say go for it. The shorter length can help for traveling, if that is your main purpose. If the tripod doesn't come with a ballhead, then you might want to look at this one:
http://reallyrightstuff.com/Items.as...head30&key=cat
I'm a big fan of RRS and I have this particular ballhead on my traveler tripod. It ain't cheap... it will cost as much as your tripod (if not more). But it's very good.
Hope that helps -