Sennheiser MKE Essential elements?

[Mark V]

The theatre where I work uses CO-8WL as their primary elements, which have served us well.

I'd like to have some less expensive lavs laying around as emergency back-ups, occasional chorus mics if necessary, and perhaps to use on our amplified straight shows if they're reliable enough, to lesson the wear and tear on our primary lavs.

Any thoughts/opinions/experiences with these? 

Thanks!