What is a better job for an E-5 to reclass to, 92Y or 42A?

Ask your self do you want to do supply or admin? Both careers relate to civilian jobs. Supply chain management and Human Resources are functions of business used in civilian jobs. Ask yourself this how well are you at English grammar and writing? If a commander asked you to review and write memos could you accurately do it? Or would you rather manage equipment and money and tactical supply suck as resupply missions and supporting the war fighters with beans and bullets? My advice would be to talk to your 92Y and 42A. Ask them questions and see what they do. Write the pros and cons of both then make your decision

Depends on your end goal and lifestyle choice. Both are good, stable jobs that offer broadening assignments, a variety of locations, and have good promotion potential.

From my experience it is much easier to move up into rank in the Quartermaster world when it comes to senior promotions. However it depends on you. Would you rather work human resources or logistics?

42A allows for more opportunities post Army career as long as you earn a degree during your time in service. Where isn't Human Resources used........?

What do you enjoy doing? What do promotion rates look like for both MOS’s? Do you plan to utilize these skills one day when you get out? These are things to look at when deciding what MOS to reclass to.

If you can swing it, go 79S.

If you like to help people, 42A.

It depends honestly if you are guard or active, if you are guard, go 42A, there is a better chance for career progression as almost any staff job uses the 42A mos as a secondary if you are not using it as the primary, and there are more positions available in general, where as the 92Y mos becomes smaller and smaller as you grow in rank within the state, typically there is only 1 or 2 per unit at the E5 and above, and then 1 at battalion level, so getting in can be tough.

If you are active it's a different story, meaning that it would just depend on what you like to do more of, keep in mind though that a 92Y will have a lot more responsibility in keeping track of supplies and sensitive materials.

At the end of the day though again it's what you want to do and what you think you will be best suited for in helping the military grow.

42a. It is rewarding and it is one of the few MOS' where you do your job everyday

Depends. If you like to be sitting down all day, you would like being a 42A. But being a 92Y will have you moving all day long.