If SWA does in fact purchase F9 Im gonna assume that there won't be an integration, with that Im also going to assume that the F9 opinion will vary widely based on age and seniority. If your 55 I don't think you are gonna want to be starting out on the bottom of a seniority list at any airline. However if your 35 and have half your career in front of you then SWA is ideal because most pilots would be completly happy making a career at SWA.
As for hurting UAL... Maybe but maybe as much as you may think, SWA has just eliminated a huge competitor in Denver.
As an CHQ guy I truely hope that SWA does get the go ahead to buy/kill off F9 as the integration would have been horrible for both groups and as someone said earlier it sets a horrible precedent. I for one would much rather be given the oppritunity to be stapled to SWAs list than be integrated into RAHs. But again Im only 28.