My first question was do I need one that can hold wet food. But I learned that cats can survive a lifetime on dry food alone, so they should be able to to survive during your absence on dry food.

Then my top priority was that how much food the feeder can hold, to know how many days it can last. This is scarcely advertised by the various makers, so it took some research.

Among the wet food feeders, 6 meals was the maximum. For my cat, that's only 3 days. So I moved to the dry food feeders.

Two feeders had a large deposit:

http://www.amazon.com/dp/B01C7W697Q?psc=1 can hold up to 7 lbs. Each pound is 4-5 cups of dry food, so that's 28-35 cups, or about as many days. It's $94 with the A/C adapter. 3.5 star reviews. There were 3 negative reviews out of 11: one complained that their cat got into the feeder, and two that it stopped working.

http://www.amazon.com/PetSafe-Healthy-Simply-12-Meal-Automatic/dp/B00VIXRB6O/ref=pd_sbs_199_3?ie=UTF8&dpID=41x5CRjxuDL&dpSrc=sims&preST=_AC_UL160_SR144%2C160_&refRID=1935XREX9KQGE08C0PJY is $127 excl. power adapter that I can't find on Amazon. holds 24 cups, which is about 25 days' worth of food.4.5 stars but negative reviews say it doesn't work, clogs, cat figured it out, etc. Many more reviews than the previous one.

I chose the former because it had the A/C adapter and was cheaper. There is a Chinese version for $50 but the seller's reviews are only 50% positive and it takes several weeks to ship to the US.