Ok, we have two single stage rockets, both have the same ISP and the same mass ratio, so according to the rocket equation; Delta V = ISP * G * Ln(MR), they should have the same final velocity, however one has it's engine sized to give maximum burn duration, the other has a really huge engine and very short high acceleration. Which one gives more altitude, more bang for the buck?
The short high thrust high acceleration rocket. The long burn of the smaller engine pours a lot of the chemical energy of the propellant into lifting the propellants themselves. The short burn of the big engine converts a larger percentage into velocity. So, that means that short burn duration engines, engines that are very simple, engines that are very cheap, engines that call for smaller stage ratios and even shorter burn durations, are in fact more efficient.
Better start building really tough payloads (which are cheaper by the way), and spend a lot of time yourself on a centrifuge to build up your Gee endurance, because that really cheap ticket to space that you just bought will probably include a rough ride.
See also "Thrust into Space" by Maxwell Hunter.