I see two options for Delta if they want to continue to offer SWUs that are anything less than a joke compared to AA or even UA.

1) Reduce the restrictions on fares and institute a co-pay system (like both AA and UA have done)

2) Manage M fare cost. Over the last year M fares have practically doubled. In 2011, I paid 2,200 for a JFK-NRT RT (a little steep compared to the competition's upgradable fares, but still manageable). This year they are actually higher than the S fares (discounted Biz) at around 5k. For a highly competitive route this just doesn't make sense.

Yes, you can upgrade right after PURCHASING the ticket IF space is available in the restricted inventory used for J upgrades. You have to call in to use an SWU - can't do it online. Usually, space is NOT available until the day of departure but I have had 4 out of 5 clear either at booking or at the gate. I have a lot of international Y flights paid for by my employer, so the SWUs are VERY useful to me. But I can also upgrade my Y flights using Skymiles, so the only advantage of SWUs is to avoid using miles - but 4 SWUs are certainly worth more than 20K miles if you fly Y, B, or M internationally.

I agree that they suck for international, but domestically I have used them several times for vacations.

I got SEA-ATL-FLL at a $200 price (L?) and used the SWU to get Business for 2 people on 3 trips so far, so they work for me.

I save the miles for the expensive europe award tickets (150K each).

You just have to figure out what works for you and use them wisely and for your type of travel.

1. The YMB thing has been in effect for about 15 years, nothing new here.

2. I have earned and used over 100 of them, no problem, if they were transferable i would ask for yours.

3. $900 vs 1900, Y vs J? I and most other frequent fliers would take that IN A SECOND.

4. Those of us who regularly fly up front would rather NOT see people on the lowest possible fares crowding out the J cabins.

Z bucket must be available. Again, the T&C are your friend... or when they're not your friend at least they're informative...

I too have used them domestically on "important upgrades."

Bear in mind you still need inventory available (and you cannot use them on L fares or U,T either)

It's not the only reason there aren't seats available, but you kind of answered your own question. If Z isn't available a lot of people will instead buy J. You did it; I used to do it all the time.

As far as usefulness of SWUs - back in '08 thru '10 when paid J was no longer the cool thing to do I had pretty much a 100% hit rate using SWUs. Once things tightened up and companies (including mine) started paying J again, finding advanced Z inventory got a lot harder. At least for the routes I travel. I no longer choose SWUs. It's a chore to use them, the process would sometimes backfire in spectacular fashion, but mainly I was finding that 90% of the time Z wasn't available at booking (1-3 weeks out) and I wasn't going to risk the gate upgrade game. Paid J it is. I'm sure there are a lot like me out there which is a huge win for DL... These guys aren't dumb.

I wish I had taken the SWU. My company now allows Y/B class flights on long haul overseas flights. The policy change came after I selected my award. I got 25K miles but spent another 75K for the upgrade of my Y/B fare.

Next year I will select the SWU and with my luck, it will be just as my company pulls the ability to fly Y/B fares.

Live and learn...

Remember also that SWUs can be used for day-of-travel domestic upgrades on K+ fares.

Assuming a DL rep has coded the SWU correctly, DMs and PMs using SWUs float to the top of the BF UG list...even ahead of those on full Y fares who aren’t using SWUs. PMs even “outrank” DMs seeking UGs, but not using SWUs. If you don't get the UG, you do not lose the SWU.

If PMs do this 4x/yr, they’ve saved at least 50,000 SMs, many more than the 20,000 they can select as a Choice Benefit. I don’t understand why PMs who regularly fly transcons or other long segments aren’t all over these. DMs, too, for that matter.

As always, however, YMMV.

I'll trade you 20,000 skypesos for the swu certs.

I book on the phone, tell them where I want to go and when, ak which routing has SWU confirmed open. I don't use them unless I clear at booking. I have always used mine, they are not useless

This. Using SWUs to upgrade W to J on AF is great, but when things don't work out that way I use them for exactly this purpose. As a PM on an M fare I gladly burned a SWU to ensure that I get into J on the 777 LAX-ATL Saturday morning. I've also burned them on red-eyes where I didn't want to risk being stuck in Y. Even if you only use them domestically on BE-equipped TCONs they're still worth way more than 20k Skypesos.

Can these still be used on AF metal either as DL W or AF S? If so, valid for companions on same PNR?
That's about the only place I see some value in these.

^ I use them this way as well. They are very useful to me for snagging upgrades on the difficult ATL to LAX and back routes.

Yup. Just yesterday, I booked a DL W fare on DL.dumb and then called to use my SWUs to upgrade. Agents had to recode the DL-coded flights to AF, but once they did, there was no issue applying the SWUs. My only issue was I couldn't find G out of SAN on my day of travel (that would get me to YUL in time for the AF flight), so I just have to hope the SWU gives me the needed boost to score the upgrade on that sector. W was £1225, M was £1900+, and discounted biz was just over £2000. I'm happy with the value I got out of it.