The large pixels don't bother me at all, I definitely prefer the larger screen over the smaller one (I had both, sold the original 3DS and kept the XL). And I think you'll get used to it quickly if you get an XL, even if you hate it initially. Have you seen
this thread? It seems that there are different types of screens used in the New XLs, and I don't think all of them suffer from the "pixel shimmer", unfortunately there is no way of knowing which one you get before trying it. If you can make the store let you open the box and turn it on before you buy it (or if it has a good return policy), that might help.