Hey
My experience - UA ticket issued from MEL-JFK in Y. Phone UA in AU and applied for 2x 30k miles + $600 copay - both ways waitlisted from MEL-LAX and SFO-SYD. Used x2 Regional Upgrades to upgrade PS SFO-JFK and v.v to C - both cleared as avialability for NC was good
later that day on united.com under travel options was offered a US$1220 upgrade from Y to F for MEL-LAX Paid it, credit card charged. Phones US Mileage Plus back, had 30k miles put back into my a/c and left 30k deduction in place wailtisted for SFO-SYD
At gate in Melbourne and at baggage drop was interrogated and stood for 45 minutes whilst the Continental US agent who identified herself as such (Ms Ellis Baldevia) told me United would rectify the situation as paid upgrades =not allowed from Y to F through the united website
After this situation I said I would not fly and would refund my ticket - left standing there and evetually an Australian United agent told me they would honour the upgrade I was then allowed to board

On a separate mileage run JFK-LAX VV had upgraded to C on PS from Y with mileage upgrade award - no problem - On checking seating at LAX at united machine was offered a elite maximiser and miles maximiser which I paid for all ok but no receipt and the united service staff could not issue me with a receipt as their systems were not working properly
At gate for PS flight LAX-SFO UA890, LAX First class lounge agent came up to me and said hello as she remebered me from being in the LAX Int First Lounge upon arrrival from MEL on Sun 3rd march - nice touch very friendly and the fact someone remembers you and just wants to say hi - gives u a feel good feeling- happens often with lots of mileage runs on PS JFK-SFO/LAX vv - that is what I'm used to with the old United and one of the things which keeps me flying with United over using AC to JFK and also to/from EU via USA with UA to maximise my Mileage Plus a/c and status and also my LH Senator status
Anyway we boarded the plane , were about to take off, told we had to go back to the gate. We were kept on the plane and tol;d they had ordered a part for the 757 and they would install the part - lots of drinks passed around - after 1 hour we were told to deboard the aircraft as the 757 was not fit to fly - no rebooking or anything - no gate staff so went to service desk and was told they were bringing another plane for us which would depart at 1935 (instead of the original planned 1330) - no p-roblems mileage run for me but not nice to arrive at JFK at 330am!

For return flight to AU online checkin on 9 March in NYC offered me a US$1729 upgrade from Y to C- for SFO-SYD sector only (still had to fly in Y+ from SYD-MEL on an empty plane but thats ok for a 1 hour flight on a 747) - paid the $1729 (after noting I was also offered earlier a US$5731 upgrade from Y -F which I declined on earlier on 9 March) and selected my seat 6J
Onboard another guy said we had the same seat - I'd been upgraded to F for my SFO-SYD sector but no-one at the gate had told me when I boarded - that was koo land a nice redeeming touch from United given the earlier botchups in Melbourne and LAX which would have given a less patient person a stress-induced heart attack
So I telephone Mielage Plus today in AU -you get a Singapore call centre - asked to have my 30k miles recredited for the waitlisted upgrade from Y-C as I had paid the upgrade fee offered at online checkin - Singapore agent tells me she cant recredit - email me ur etik receipt (which clearly states -under adddtional charges
Thu Feb 9 Amex xxxx was charged US$1220 for the following: First Class Upgrade Fee
Thu Mar 8 Amex xxxx was charged US$1729 for the following: First Class Plus)
She cant see my etik receipt so she can recredit the miles? She wants a copy of my credit card statement -

After all of this Im cancelling my upcoming ticket - LX/LH half tiks with UA sectors MEL-SFO in Z and LAX-MEL in Z - have to call Lufti and check AC availability SYD-YVR v.v I've had it with United
Toothpicks gone in PS C (they were there Sunday , gone Tueday, and again on Friday
PS crew have changed it seems - u ask them and they admit they havent worked PS before
Toothpicks in F from SYD-LAX last Sunday, gone yesterday from SFO-SYD
Nice new touch though - chees fruit trolley which Ive never seen in F before - used to this in LX/LH/SK C)