I just bought a mvvs 160 gas engine with vlach ignition (two magnets). I know there is also a different ignition for these engines called just electronic ignition with one magnet. What is the difference between these two systems other than that, which is the best one and why?

If this is like the 3W ignitions, then it has a built in tach to get RPM readings.

The difference is in the timing algorithm, and added safety features that can be used with the added magnet.
Vlach (current MVVS production) has the magnets currently at 180 degrees interval (one spark- and on timing magnet). This ignition cannot differentiate between forward and reverse running. 3W has the timing magnet 90 degrees before the spark magnet. This ignition will notice the difference of reverse running, if programmed to do so. All two magnet ignitions do not require remapping, because that is handled by the second magnet, which as added safety feature also resets the ignition, so it can fire again.
The single magnet ignition (Falcon and obsoleted Vlach) with the hall sensor in TDC need a lot of delay calculations to determine the exact ignition firing point. They operate with a slight timing lag, and often need to do some re-mapping, which may cause a single misplaced firing pulse every now and then. The human ear can hear this.

The single magnet ignitions with the sensor placed at over 30 degree advance have easier firing delay calculations, and IMHO work a bit better, because no remapping is required. They have the drawback of sometimes viscious kickback, and need a firm gloved hand or chicken stick for starting.

thanks preivers. very informative