selecting an electric water heater

Hello all. i am in need of a little help on the best water heater to buy for the money.

right now, i have an A.O. Smith water heater.
50gallon, 53-1/2" in height

i realize AO Smith is one of the top water heater brands but at this current time, i cannot afford to replace our old water heater with the same brand.

i am looking at Home Depot and see a couple in the 50 gallon range and they are being classified as 50 gallon tall and 50 gallon.

the 50 gallon tall is about 4 inches higher than what i have now and the 50 gallon regular is about 6" shorter than what i have now.

what route should i go? s the warranty time that critical? they come in 6/9/12 year.

any advice?

thank you in advance
Shawn