I have a 60 series Garmin GPSMap, and it has been an excellent unit.
I have used it on my sled in the winter and dualsport motorbike in the summer for the past 5 years. Covered in snow and ice, or mud and water, it keeps going.
I have a Lowrance and love it. I have the snowmobile trails on it as an overlay. Sweet set up. I also use my phone (droid 2) as a gps and navigator. Just for giggles and grins I found a phone App and loaded an old fashioned compass on the phone it works quit well.
I bought it Bass Pro Shops. It did not have the trails but you can download them. (Some help from others here please) It did have all the forest roads which is all I was interested in. Without the TOPO card, It won't do you any good for sledding.
Lowrance topo maps are pricey. You buy from them and the sell it in sections. $60 got me most all of Tog. Area to Lava mtn. It's like a dollar a sq. Mile for topo maps from Lowrance.