Currently i am AA Exec Plat, I have no experience on the sky team network, but I will need to fly with CO and DL this year, LGA/JFK is more convinient for me then EWR, but EWR is not bad, question is should I make a onepass account or a delta skymiles, (both will status match me) I have heard that CO F is much better then DL F domestic flights, on the other hand I have heard that on CO out of EWR you almost never get a upgrade,

also do one of then have like AA the evip?, how can I upgrade internationaly ?

next question who has more seats avalible for international award tickets, (this is where i use the mileage) do they have more options for elite ?

Delta offers a PMU for their platinums (top tier). It is an international upgrade certificate but it requires a Y/B/M fare, which are the three most expensive, and is capacity controlled. Continental does not offer any SWU-type instrument and there is no indication that one will be forthcoming in the near future.

Upgrades are easier on DL based on most accounts, but I was ~90% out of EWR last year (mostly on EWR-MCO/TPA/DAB/JAX runs) on CO. It depends a lot on your routes and travel times.

If you are actually going to be flying on both carriers then also consider the 50% EQM/MQM issues. Both carriers only give 50% EQM/MQMs for the lowest fare on the other. CO also has 50% earning for NW flights on cheap fares; DL earns 100% on all NW fares.

DL is a miles-based qualification only, not points/segments. This extends to CO credit on DL metal where you'll only get miles, not points (and potentially only 50% miles as noted above).

CO does have more seats available for BusinessFirst rewards for their elites, but that doesn't mean that there are a lot of them. I don't know if DL has a similar offering.

DL has also just reduced the availability of their 2x miles reward seats, or at least that was the case a couple weeks ago; I haven't followed up on it since I got back from vacation yesterday.

The other option would be to get NW elite. Same upgrades (or lack thereof) on CO metal but no 50% EQM earning on DL. Of course they do have 50% EQM earning on CO cheap fares so that may not help as much.

I think that in your case DL makes more sense if you are going to fly them more out of LGA/JFK, where they have a ton more options.

S.

One thing to consider is that NW also offers SWUs. In 2007 you could earn 2 SWUs at 120k miles and another 2 SWUs at 160k. (2008 program rules are being released on 1/17, but it is believed that it will get better not worse, with additional earnings past 160k). These SWUs book into C class for international (which is slightly discounted business class, but not full discounted business class, so availability is very good) and can be used with a ticket in any fare class, not just Y/B/M. They are good on NW transpac and NW/KL trans-atlantic flights (and also NW domestic, but why you would waste it there I have no idea).

You can usually find a CO fare that will earn you 100% to NW without paying much more, and if you're doing business travel I can't imagine it being a problem. As for INTL award tickets, NW sets aside additional availability for elites (and I believe even more for platinums).

As a NW elite, as said before, you get upgrades on NW and CO (and also AS), as well as 100%/150% miles on DL. One other thing is that both NW and CO give 125% bonus to plat, whereas DL only gives 100% bonus to plat for earning miles (RDM not qualifying miles).

So, I wouldn't discount NW. You might also consider flying NW as well, depending on your routing (especially if you are going to have a stop anyways, but if most of your flights are direct from EWR/JFK, then whatever's convenient...)

Also, not terribly important, but Continental offers free meals (in both Y and F) on most flights, while Delta does not on most. Continental F domestic service is still OK, while Delta F is sometimes nothing more than a wider seat.
If you have money to blow and time is tight, there is helicopter service to the airports from Manhattan and other locations. Continental also offers mileage for certain Acela and northeastern Amtrak routes. Continental also gives 50% bonus for Silver while Delta offers 25%.

Helo service is available to DL's JFK T2/3 as well, though CO does give EQMs for the service if booked as a code-share add-on to a connecting CO flight to/from EWR. DL's Platinum bonus for RDMs is only 100%, same as their Gold, while CO's is 125%.