Warfarin needs to be adjusted because of variability in the way the drug is metabolised. This is also effected by lots of other things. The newer drugs are just a set dose and no monitoring. All drugs have side effects and 30 seconds on Google will be enough to terrify you, but I find these drugs well tolerated. Long term drugs I agree are a separate concern, but if you need long term anticoagulation (not everybody does!) I would rather be off warfarin simply because the risk of under or over medication is far more likely than long term side effects.