The VR3 actually uses the same model as ProPlanner, not DecoPlanner. If you buy the download kit for the VR3 (which is very handy if you dive different mixes regularly) you get a copy of ProPlanner as well. Taking tables in with you is very important as they act as a simple, break-proof lifeline should anything happen to your computer (i.e. it fails, falls off, etc.). I memorize my planned bottom time and refer to them whilst doing my ascent as a backup to the computer. If the computer gives me off results then the tables take over.
Personally I use ProPlanner for cutting my tables and compare them with ddPlan for a quick sanity check.