I fly either Jetblue or SW.....from Mass to MCO...all the time.
I like SW, especially now that they have fine tuned their boarding proceedure.
You book your flight....then, you can buy, for an addtl $10 pp each way, Early Bird checkin. This allows SW to automatically check you, and anyone else who has bought EBCI, in at the 36 hr mark, before departure. If you don't do that option, then you need to be online, at the 24 hr window, to check you and your group in. This simply means that if you have a flight that departs at 2:45pm on Sat, you need to be on the computer, ready to get checked in, no later than 2:45pm Friday.
So.....what does all this mean? It means that SW boards by group...A,B and C. Within each group are smaller groupings...1-5, 6-10, 11-15, and so on..up to about 50 (for each group). Your boarding pass (from when you checked in) will have a letter group as well as a numerical group....A23, or B13..or whatever. When you get to the airport you will line up, according to your boarding pass groupings. A1-15 slots are held for business select passengers or passengers who have paid the fully refundable fares..usually pretty expensive.
Anyone with children under 4 is allowed to board inbetween the A group and the B group...but only immediate family!!
When you board, you are allowed to choose whatever seat you want, from those that are currently not taken. So, obviously, the lower a number you have, gets you a better selection of seats. A16 gets you a huge choice, while C45 is going to be pretty much take whatever is left!! Each person in your group will get a boarding number of their own...and there could possibly be a break in between the numbers, but that's not usually an issue. You can save a seat or two.
Other good stuff....SW allows 2 checked bags for each person that has purchased a seat. SW seldom makes any changes to it's flights once they are posted. Yes, they do wait longer to post fares, but once done, they are pretty set in stone.
I really like SW....I have had very few bad experiences with them. The boarding process can sound daunting but it's really easy to figure out. Sounds worse, when being described, than it really is.