From looking at the Wyeast site, they are not terribly different, at least not enough that it will make a huge difference in the beer. Both strains are recommended for dry stouts, so you should be ok.
The flocculation is noticeably higher on the Irish Ale yeast, but other than that, they are quite similar. I do have a couple of questions though. 1) What temp are you fermenting at? 2) When you say stuck fermentation, can you tell me a little more specifically what you are seeing that makes you say it's stuck?