My favorite hard cases are the ones from Pono, and my favorite gig bags are the "
Steady" brand, which seems to now be called Fremont through Elderly. Nice accessory compartment and stowable shoulder straps, and a good comfortable molded handle. There is much to be said for a brightly colored gig bag, especially if you go to uke festivals or jams. There can literally be hundreds of nearly identical black cases running around.
https://www.elderly.com/catalog/prod...category/1145/
https://www.elderly.com/accessories/...-cases-gigbags
Cordura covered poly foam cases are fairly inexpensive and provide good impact and thermal protection, but the zipper allows moisture to easily escape, so they are not great for maintaining humidity. With gig bags, I need to re-wet my sponges about twice as often as in a hard case.