If you get the pressure drive, I suggest the longer models. Double check the exact model specs- max pressure, etc. to make sure you get the right model, they make a whole bunch that look similar. Lezyne isn't the cheapest stuff, but it's about the best made for the price.

The Micro Drive isn't TERRIBLE as a frame mounted pump, it's just a little clunky. The bracket mounts it next to a water bottle cage and honestly it doesn't get in the way as much as it looks like it might. If you like that design, look at the Topeak Road Morph, it's somewhat similar in design, though a little cheaper in finish, and a little more sleek when attached to the bike- though the included bracket isn't all that great- it holds well but it takes up a water bottle mount by design, or you zip tie the bracket somewhere (seatpost, under top tube, under downtube, etc.).

Personally, I just carry CO2 on my road bike. If you're going for a long ride, bring more cartridges and tubes. If you're riding in a group, as long as everyone has one cartridge and one tube it's usually enough even if someone has a bad day. I only bring a pump if the bike I'm riding has some sort of bag (most of my bikes).