This document is all about tissue cultured bananas after removal from the flask:
http://aciar.gov.au/publication/tr018
(Despite the appearance of it costing something, if you just hit the download button, it'll download for free.)
In short, aside from it taking extra time to get them from the "plantlet" stage to the size you might see for sale in a nursery or big enough to plant in the ground, the only other major concern is "off types" -- somatic mutants that are not true to type, i.e., not the same as the plant that was cultured. Apparently there are lots of off types, with dwarfs being one of the most common. But you can tell the off types even when they are very small in most cases.
Like Kostas and Ante said, if you are comparing a TC plant to a non-TC plant that is the same size, there really shouldn't be any difference between the two, except the TC plant would be disease free, whereas the pup from the field might not be.