I've used WY2206 a few times and M76 twice in a bock, helles and dunkel. They perform in a similar manner in terms of good floc, attenuation and low sulfur production-- much like my usual workhorse lager yeasts (Imperial-Harvest and WLP 838) that I mostly use in more malt-forward lagers. I think M76 would be fine in a kellerbier.
I've seen a few comparisons on the interwebs equating M76 to 34/70. IMO, all things held constant, M76 produces a more malt-forward, richer beer than 34/70.