Keyboard Comparison: old or new? better or worse?

Ok sorry for the vague subject but I'm a computer lab teacher at an elementary school and I am trying to go thru the whole school's tech supplies to send old/poor hardware/cables/parts back to the district office for surplus.  I really just need a bit of help deciding what is new or old, better or worse.

First up is keyboards, the school has two main models of keyboards, both of them are classified as "compact USB keyboard" on any google search I do with the model numbers (SK-8115 and RT7D50). The SK-8115 is a bit quieter and the RT7D50 is a bit faster spring-back as far as I can tell. I can't find any other info on these keyboards and the difference between them really...Like I said my google searches have turned up no real specs on these products just a couple independent reviews for each. No problems with these products, they are cheap enough to replace anyway.

My question is: 1) Which is better for kids to learn how to type? quiet and smooth or loud and responsive? 2) Which is older and which is less popular or a lower quality product? They are both cheap but are fine quality to me I just have about twice as many than I need at my site haha.

Thanks for the help,

Chase Calkins - Computer Lab - Anderson Elementary School