Well, regarding train service both are similar.

From Bingen there are two (local) train connections per hour (weekday incl. saturday).
One of them is a direct train (no transfer needed / travel time 2h30mins) and the other requires a transfer at Koblenz (travel time ~10 minutes more ...).
The downside is that Bingen is probably less interesting in regard of touristy things.
Have a look at the city of Bingen`s website: https://www.bingen.de/en/tourism-cul...iscover-bingen

Rüdesheim is much more wellknown among tourists and likely more attractive.
... but train travel to Cologne always requires a transfer at Koblenz. Travel time is similar to that from Bingen but trains only run once per hour.

If you have enough time (I know that´s "relative"...) you might even combine both cities - which is easy as there´s a direct regular car/passenger ferry between Bingen and Rüdesheim.
IIRC it runs every 20-30 mins and crossing the Rhein river takes approx. 10 mins.