In a nut shell:
Mainline United will put you at 8A status(highest non-rev) on mainline and UAX, UAX employees will get on ahead of you on their own flights. Unlimited standby, coach is 100% free(just return taxes for intl travel) for the employee, children, spouse, and parents. First class is mileage based, $25 for flights less than 500 miles and up from there, SFO-SYD is like $300r/t for 1st class(including taxes), a $24k roundtrip ticket, not bad. All these fees come out of your paycheck, you never pay up front but you can choose to pay by card when they process. If you aren't married, every year you get to pick an enrolled friend who travels at your priority unlimited for the same fees as you, except you get taxed at the end of the year on their travel, you can look up the fees on each flight, they are nominal. Last year my girlfriend flew about 20 segments, including HKG and a bunch of first class, and I got billed like $400. You get 24 buddy pass segments, they are 10% of the full coach unrestricted fare so they vary. The norm is about $75 roundtrip for flights under 2 hours, about 100 for flights under 4. Some are oddballs like SFO-SBA costing more than SFO-HNL and SFO-YYZ costing more than SFO-SYD. Again, these can be looked up, and its all electronic so you can list people at the last minute. UA does comp upgrades now, since they started it is very, very rare to get first class on a 2-class airplane on a domestic flight. They don't comp international or 3-class airplanes, so that is your best bet for first/buisness. Employees get 2 free bags, so do buddies and everyone else on your bennies. Pretty much all UA flight crew seem to commute, so the non-rev lists can get pretty big! Bigger than I usually see on US, AA, DL, ect. They have incentive passes for first class where you get the charge waived a few times a year. There is a $50/person fee on your flight bennies per year. The cap is like $200, so more than 4 people and the rest you won't be charged for. No dress code anymore for the most part, I got on TUS-SFO today wearing a giants hat, giants t-shirt, and jeans with sandals. All in all I'm very happy with them, while I think DL has a better deal, I still think UA's are better than AA and US. CO has great benefits, so we'll see how those play in.
I will add that as far as intl travel goes, First/Biz are up to par with most other intl airlines, lie flat suites and the like. However, coach is god awful. I seriously would rather go home then fly intl in coach, and I have done just that several times.
