Both batteries are getting charged the same amount time, so they have the same amount of power.
The advantage of nimh is that they can hold more energy, but they must be charged multiple times to max them out.
Becareful of overcharging. They can overheat and melt the car, or worse, any rechargable battery can explode too. I don't want to scare anyone, but you do need to be aware of the dangers.
I found a 110 mah nimh in my $5 thundercharger! Sure, it's nowhere near your (microspeed's) 200 mah, but it's way better than the standard Tomy and MS 50 mah. I was so surprised when I first opened it up, there was a frikkin drop of spilt solder on the cell too My MS sport came with a standard 50 mah, and I haven't opened up my ZZ SE(don't have my precision screwdrivers with me )