WOW
Well...
If you are loyal to US, you can build up miles to transfer to interesting places in Canada, Caribbean, Europe, Asia, New Zealand, etc, which is not true of Southwest. Or if you don't fly that much, you could build up miles to upgrade to first class after a ticket purchase.
Also if a flight is cancelled due to any other reason, you face better protections as there is interline ticketing with real airlines - even competing airlines.
You won't get any teenage girls masquerading as flight attendants singing stupid karaoke songs on the descent into Albany. Whether or not that is an advantage or disadvantage is up to you.
You will get an assigned seat that you have a chance of changing in advance, as opposed to herded onto the airplane like a cow.
And, most importantly, you will deal with more experienced employees at USAir. You have a better chance at having better one-on-one customer service.
And, no, I am a passenger who has never received any paycheck from anyone affiliated with Usair or any other airline ever.
Depending on various random events such as a FA eating the wrong food the night before your flight, or a bad thunderstorm somewhere, or a part on a plane breaking, your overall experience on any single flight may well be a toss of the dice. However, if you fly on US regularly you have a better chance of becoming a loyal customer.
I have found the Albany gate agents to be wonderful - I've never flow into Fort Lauderdale.