So, lately there are a lot of these types of threads popping up, and I can understand. As an outsider, looking in, its hard to separate the all the information and try to make an informed decision, especially if you are talking to recruiters and also getting biased information from forums.
To start, there is not a one size fits all. And the good news is that there is more than one good choice. There are also some bad choices.
-- Look at the base choices.
http://www.pilotdomiciles.com/
Take a look at this site and try to decide where you would like to live, or where you live now. Not commuting is great. An easy commute can be alright. A cross country commute can suck. A two leg commute to reserve can be hell.
-- Trend vectors: Do not just look at a company and see where they are now, but try to gauge where they will be in the near and long term future. This can be difficult but look at various factors. If you are jumping onto the train when they are at fast upgrades, you may have just missed the train and the numbers could be swinging the other way. Look at long term contracts and company track record. If you get stuck at a regional for a few years, where do you want to be stuck? Does the company have aircraft on order? Do they own the planes? Are they getting deliveries? etc.
The OP mentioned:
Envoy - Transferring CRJ700s to PSA, but gaining E175s. They have a flow with AA. Although not the best working conditions, of the 4 you mentioned, I think this could be a good choice depending on domicile preferences
Endeavor - Fully owned by Delta. Endeavor was high on my list when I was looking at regionals but I still had Comair fresh on my mind so I was a bit skiddish. Endeavor does look like a good choice right now, especially if you are near New York or Atlanta.
Air Wisconsin - They lost a lot of pilots recently due to uncertainty of the future of the company. Now that they secured flying with United, they need to rebuild the pilot list. This could mean fast movement. Air Wisconsin has traditionally been one of the better regionals. Having said that, they have a lot of old CRJ200s, and its an all 50 seat fleet.
GoJet - People love to hate on GoJet. Just read up on their history and how they were formed and you can understand why. The have a relatively fast upgrade but people really like to talk bad about them, so do your research.
Right now, any regional will probably take you, so don't limit your research to just four companies.