I would probably get the 1602, an auto-egg turner and buy a PC fan and hook it up myself. This way, you get everything at a reasonable cost and some flexibility. I think the 1588 can also be adjusted even though it is a "pre-set" model. Given all the different incubation methods/settings available which are highly dependent on your climate and locale, a little flexibility goes a long way in my opinion. I like simple things - an adjustable thermostat that can be easily replaced if necessary, a simple fan that can also be easily replaced, etc.
I also believe in "less is more" when it comes to handling your eggs throughout the incubation cycle, hence investing in an auto-egg turner. The kids should enjoy the "hands-off" approach but also still able to candle, observe, make adjustments and try their own settings and experiment. Really, who enjoys a black box approach?
I am no expert. Just my 2 cents.