You need to trial them yourself, only you will know which is best for you, also for your reference the Rexton (Signia) are also available from Costco, these are just as good as any of others.
I think both the Philips 9040 and the Jabra Enhance Pro 20 are both already available at many Costco. The Philips 9040 has 2 notably new features compared to the 9030, and they are the sudden sound stabilizer and the wind & handling stabilizer. I’m not too familiar with the differences between the Jabra Pro 10 and 20 so I’ll refrain on commenting on those.
If I were you, I would ask your Costco when those 2 new versions will be available to see if you can wait or not. If not, then if you decide to trial both, then pick one first and try it out until the new version of the other one becomes available. At least you’ll get to try out 1 of the 2 new versions of one of those 2 brands.
Yeah we all have our favourites, personality i don’t bother with Oticon/ Phillips, they have a different way of processing that doesn’t suit everyone,ReSound (Jabra)is another favourite and quite popular as you’ve noticed, do the trial period and see for yourself which you like, but it’s strange about this particular Costco outlet stating they don’t have and don’t know when they are getting them, as they have been released, are you in USA?
Your best bet is to try both in the store and choose whichever seems best. They’ll do an initial fitting for both aids, and the better sounding one is likely to be the better choice for you.
I chose between the 9030, which I used for 10 days, and the Pro 10s. I thought the Pro 10s were better in that voices seemed sharper, clearer, and easier to understand. But your experience is likely to be different.