I am considering upgrading to a power tongue jack. Couple of questions:
(1) What make/model jack do you have?
(2) Any reliability concerns with your jack?
(3) What options do you have if the jack fails in either the up or down state?
Here in Canada I usually wait for a sale at Princess Auto (something like Harbour Freight in the US) and buy one there. They have one on sale right now for under $60 Canadian.
I have never had a problem on any of my trailers as the jack is usually over rated for what I need.
Most jacks have a plug on top that you can remove to insert a manual crank if the power or motor fails. While in storage I always put a bag over the top of the jack to ensure no water enters.
The jack is held in place by 3 bolts so very easy to replace.
As an extra note: If put a secret switch somewhere that provides power to the jack it makes it not as easy for someone to take your trailer.
Good luck on your purchase.
__________________
So many modifications...so little time.