I use both in my courses but prefer the Silva Ranger as the bearings and tickmarks on the compass housing are easier to read. Remember that a compass of any kind can be drastically affected by iron ore deposits in the ground, mining activity (which can be commong in places like Alaska and Canada), powerlines, if used inside your vehicle, proximity to a jacket's metal zipper, and in one case I know of, when read to close to a woman's wire-rimmed bra.
If you aren't versed in land navigation and map-reading, consider taking a short course to familiarize yourself with the basics of shooting a bearing, adjusting for declination, boxing, triangulation, and barehanded methods. You will also want to find out what the current magnetic declination is for your state as most topo maps are 10-40 years old and have an outdated declination. Adjusting for magnetic declination is critical or you will end up lost! Go to www.usgs.gov for more information on your region.
With the arrival of GPS, map and compass skills have languished or disappeared amongst outdoor explorers and in some cases, amongst professional guides. There is no substitute for being able to navigate through the wilds with a baseplate compass and a 7.5-minute topographic map. Outdoor gear shops like REI offer 1-2 day courses in the basics and chances are that there is an orienteering club in your region that provides weekend events. Short of that, everyone should have a copy of the classic book "Be Expert With Map & Compass" at their disposal. This will show you the baseline skills for coupling a compass with a topo map. One last note, a compass that gets a bubble in the liquid housing should be discarded.
