LeapFrog® Leapster® 2 Learning System- green Review

I just bought this Leap Frog Leapster 2 Star Wars design Product and my 6 year old LOVES it!  I bought it on a whim at Target, #1 because it was 1/2 off (39.99 from 79.99) and #2 because it was the Star Wars theme with a free Star Wars Math cartridge included.   The cartridge alone costs $24.99 so I think I got a pretty great deal.  The game comes in 3 levels  with number 1 being the easiest.  I have found that my 6 year old is very good at the 3rd level (the highest).  There is another math game for I believe 6-8 year olds and I think I will buy that for my 6 year old next time they are on sale.  I looked online and saw there are a ton of different games for the kids and they feel like they are "playing" instead of "learning".  My 4 year old is getting into playing the 1st level and he is doing terrific too.  This game console is also very cool.  The screen is a good size and unbelievably clear, there is a stylus for the kids to use (conveniently attached) and the size is just perfect for small hands.  The only problem I have is the batteries don't last very long.  A rechargeable unit would be absolutely ideal.  Maybe something to consider for the next model?