When I was in your shoes 8 years ago i had a very smart professor tell me this during a long conversation.
"This is a very funny industry, you are going to have friends that go one place and upgrade very quickly. You will have friends that get furloughed. You will have friends that go to a company that shuts down or in this day gets purchased, merged, torn apart, etc. Go to every interview you can get. Why? Well you don't have any decisions to make until you have an offer in front of you. This also allows you to get a lot of very valuable interviewing experience. So then which one do I choose? The one that offers you a class first. You live and due by your seniority number."
I know some of that conversation is out dated but I believe it has some very valuable lessons for everyone coming into this industry. So my advice, go to as many interviews. Get a feel for each company and make a decision from there.
Here is how I see some of your choices.
PSA - Growing at the expense of other companies. We will see if they actually get all the jets they say they are getting. If I had a dollar for every time I heard "we are getting X amount of jets" I wouldn't be in this business anymore. They have a quick upgrade right now which is good. They have a interview program that has about a 98% success rate. To my knowledge of those successful they move 48 to American per year (4 per month).
Mesa - I don't know a whole lot about them, just their reputation precedes them.
TSA - Growing at the expense of another company. They have a CQFO program that won't do you any good as you will not have the time to be a part of that program. They are owned by ruthless people. Do your Go Jet research and see how that whole thing worked out for TSA.
Compass - Griwing from pure growth, not taking any airplanes that are at other companies. They have many pilots that are flowing to Delta creating guaranteed movement. Once that is over well that is the wild card as to what happens as far as upgrades. The company is good, the people are good and there is a lot of 121 experience there. That meaning most if the pilots there compass wasn't their first rodeo.
Endeavor - Shrinking to a point then what? Who knows what is going to happen there once they get down to 81 900s. What is known about them is they have the most movement to Delta than any other carrier in the world. They will send 144 guys to Delta next year and those numbers keep going up in the following years. They just signed a deal making them the highest paid first two years in the industry. They have a fantastic training department, regarded as one of the best in the industry. If they can hire I would say the sky is the limit and you can expect not to be an FO after year two. Most of the bad press Endeavor gets is from former employees that just relay information from their negative friends here.
With all that being said, there are a lot of choices out there. Take what you read with a grain of salt. Again take as many interviews as you gan get and go get a real feel for the company when you are there. When you are traveling to the interview ask their employees questions and really get the temperature of the employee group.
Good luck with your career. It is an exciting time to be joining this profession.