I am a frequent to heavy traveler and tend to go through bags every 4-5 years.
I prefer to travel with carry-on luggage for expediency through the airport/flight, to prevent lost luggage, and enhanced items access and security. This is my first Tumi and first impressions are positive, with one gripe.
First the good:
Quality: the bag has a very high quality in build. The material seems top notch, and well stitched. Zippers seem strong and are sealed from weather. I cannot comment on how well the zipper pulls will stand up to the luggage handlers and carousels; the pulls usually tend to get caught and ripped out...
The size is perfect to outstanding for overhead luggage storage in the cabin. This bag is especially optimized in fitting the maximum amount of items in the airplane's overhead compartment, and to do so it has been "bulked up" more towards the top end of the bag, while the wheel side is a little slimmer. As a result when the bag is inserted in the overhead compartment,  wheel side in first (this is the intended orientation) the slimmer end of the bag fits deeper in the compartment, while the top and bulkier end of the bag takes up the more available space that's closest to the aisle, which otherwise stays unused in the outer end of the compartment. Good trick, and good execution. This arrangement would be top heavy and can potentially compromise the stability of the bag, but so far I have noted no such issues...seems Tumi added capacity to the bag, while solving this potential stability issue of a top-heavy bag.
The exterior pockets are good and very useful. Someone else noted the first pocket is not double-zippered (with double pulls)  and that is a valid observation and a concern, although minor.
The interior of the bag is well done, with dual zippered pockets and liner. The liner is my real gripe... The liner is under-sized in fit. The sizing of the liner - undersized as I observed - prevents the effective use of all the available space, especially between the pull bars. Not sure why or how Tumi missed this...but this is an issue.
The wheels are larger than any I've seen and roll well. Note there are only two wheels - which is my preference, vs the 4 spinner wheels we see as an alternative.