All depends on what the deal is, the deltas with your current benefits, and where you are in your career.
If you can pick up pension credit without having to commit to staying for a long time with ExxonMobil, it may be worth taking the offer.
If you work in the Dallas office, expect to have to move down to Houston at some point to stay with the company.
The 401k options are very, very limited. Basically just a few funds which track the S&P 500, Total Stock Market, International Stock Market, and Bond Market.
The health insurance has good coverage, but it's going to cost you more.
On the plus side, if you have more than 5 years of experience, vacation time may go up.
Work life balance seems to vary by role, work group, and personal ambition.
I'm an experienced hire who worked for oilfield service companies. Still better than those companies, but ExxonMobil is also actively moving to be more like them so not as good as when I joined 5-8 years ago. When I joined, I thought that it would be the company that I could retire from. Now I know that it's highly unlikely to be since ExxonMobil is trying to be more like other large companies where college hire to retire careers are more the exception than the rule.