I'm planning a trip to Japan and long story short I am taking a domestic flight on AA and then at LAX connecting on to SQ. I have about a three hour layover on the way out and two hours coming back through LAX. So coming back especially I am very concerned about making my connection. Normally I travel with my backpack. I have used it for longer than I can remember and it has been with my to a ton of different countries. The problem is it is 24 inches long and I think the AA cutoff is 22 inches. I typically check my backpack so I don't need to worry about carrying it around with me in the airport. Since my connection is tight this time I am thinking about maybe buying a carryon with wheels.
Does anyone have an opinon on whether a backpack or luggage is better on a trip? I'll be in Japan for two weeks and moving around a fair amount. I always concerned a backpack a simplier solution because you can use it even when there is no sidewalk or pavement. The tradeoff is it can get quite heavy over a long distance and isn't the most pleasent thing to lug around on your back. Not to mention I feel a bit sketchy showing up in a nice hotel wearing a backpack. Also, does anyone have recommendations of a good carry-on? I'm not trying to break the bank here with the purchase but I have a $50 giftcard for Macys which could take a bit of the sting out of the purchase. It seems like most the bags they sell have four wheels now vs the traditional two wheels I am used to seeing. Four wheels work better than two?
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I don't know if this will be helpful or not, but back when I was still traveling I had a backpack that had two small wheels and a pull-out handle - it was the best of both worlds.
It wasn't exactly perfect (the handle and wheels, however small, did add bulk) but I could either wear it on my back or pull it behind me.
I do not remember the dimensions, but it was larger than a "normal" Jansport-type backback. It might not be what you have in mind (and I'm not sure if Macy's carries such a product) but it served me well. 
@UncleB wrote:I don't know if this will be helpful or not, but back when I was still traveling I had a backpack that had two small wheels and a pull-out handle - it was the best of both worlds.
It wasn't exactly perfect (the handle and wheels, however small, did add bulk) but I could either wear it on my back or pull it behind me.
I do not remember the dimensions, but it was larger than a "normal" Jansport-type backback. It might not be what you have in mind (and I'm not sure if Macy's carries such a product) but it served me well.
I had something like that once. It wasn't the most comfortable and I think its better to go with one or the other instead of a compromise. Thinking over it it is all coming back to me about the straps digging into my shoulders and the major PITA it is taking a backpack into subways etc where you need to take it off then put it back on etc.
I usually travel light so only these 2 for me (they're both from Tumi). Both been with me for over 3 years and never have any issue (most of my trips are overseas and around 3 - 4 weeks). 
@tacpoly wrote:
I've done both, but have lately been using a 4-wheel carry on (Rimowa Salsa Air Ultralight) because for all my travel now, I go from the airport to a waiting car service.
If you are hitting a lot of cities and are taking public transport for most of them, then I would go with a backpack. However, I would use the convertible packs for most flexibility unless you are camping (Patagonia MLC or Ebags Motherlode are good). The important thing is to pack light - no matter what luggage you use - and keep it to carry-on only.
As for your pack being 2 inches too big, as long as it's not stuffed to the gills, your backpack should be fine as it's a soft luggage; you can punch it down. For the tight connection, as long as your flight isn't delayed and you don't have to collect any luggage or go through security again, you'll be fine. I have heard of airport concierge services that will expedite transfers -- perhaps you should inquire about that with the airlines or airport if you are worried.
BTW, one good thing about backpacks is that it tends to get weighed less often. I've checked into a Luftansa flight (business class) with the pack on my back and they didn't even ask me to weigh it. But I've done the same with a wheelie and they always ask me to put it on the scale (business and first class international). I avoid this altogether by doing electronic check-in if available (not that I'm worried because I'm not even close to the weight limit).
In LAX I have to go through customs and my understanding that going from the international terminal to the domestic terminal for AA which is next door and requires going through security again. I am very concerned about the flight back. The flight out I have a bit more than 3 hours which should be more than sufficient. Points in my favor are I have GE and precheck. I am also flying SQ in F so I will be one of the first people off the plane. Also, since I am arriving on a Sat afternoon around 1:35 I would think there would be less people, but I could be wrong.