In many cases I like to buy a travel version from whoever makes the fragrance; Guerlain make purse sprays for many of theirs, Annick Goutal make 10ml sprays and roll-ons, etc. Roll-on bottles are probably the best in my experience, but some light scents do better in a genuine atomiser. I don't like the travolo type, partly because I own too many splash bottles, but also because I find them a little ugly and dislike that each can only carry the one scent. For something cheap I usually go for those little roll-on bottles as they waste less, but these are generally for home use.
I recently bought four nifty little 5ml chrome atomisers (fairly standard construction) that look nice, and the Ebay shop I bought them from engraved each for a small extra cost so I had these customised for individual scents, but normally they're about the same price as those travolo ones. I always carry something though whether it's a 'travel-sized,' version of a scent I like, or something I've decanted myself as there are many situations which can result in one needing to freshen up, and many nice fragrances that lack all-day longevity.