I would do neither.
1. One of the joys of using a Leica is the viewfinder. All M previous to the M4 have a blue tinted finder which is not as snappy as the post M2 models. Plus, you need to see the camera and have familiarity to avoid a bad deal. A reputable dealer or knowledgable friend can guide you.
Note. Most older cameras will need an expensive CLA.
However, if these were my choices and I was just thinking of use, not recovering value....I would go with a M2 and 40 if it had the hood. The angle of view for a 40 matches the field of view for the .72 35 frame-line. A clean 40 is a bargain. A Cron 35 is normally over $1400. The 40 records as well as a 35, especially for small 5x7 enlargements. The 40 is a great all-rounder and either a Leitz or Minolta 40, give or take, as good as a Cron v1. Get a vintage camera case to cover up the beauty marks.