i have an explorist 500 & it's pretty good. i paid about $370 for it plus i bought some software from magellan for the eastern great lakes.
the unit is small, seem pretty durable, and has a rechargeable lithium-ion battery; a great feature for long days on the water. it also has adjustable screen brightness to conserve battery power.
there is no case included with the unit, just the reciever, and a charging/PC cord
one thing that i'm not to hot on is the software. i had to order it from magellan (had heated discussions with staff @ bass pro & lebarons over the very existence of this product), and it was pretty expensive(approx $200)
the software maps also seems to be off when i'm trying to match up spots on the lake.
however, i would say, for the price you'll be extremely hard pressed to find a better unit.