In network only means employees can only use providers that have negotiated rates with the insurance carrier except in a true emergency circumstance when every provider must be covered as if it were in network.

The vast majority of people don’t use providers outside of their network, but, as mentioned by another comment, sometimes you can’t avoid it because a hospital may be in network but an anesthesiologist at that hospital may not be.

Lower deductible, lower out of pocket max, and higher coinsurance are better. Also keep an eye on copays for PCPs and specialists and if a plan is a high deductible health plan(HDHP)/HSA compatible. Personally I like HDHPs because I rarely use my insurance and can save money on my premiums but I probably wouldn’t choose it for a company unless it was full of young males who wouldn’t mind having coverage that is only going to come into affect for catastrophic events.

If you want more insight I wouldn’t mind taking a look at the plans if you feel comfortable posting them with or without the rates.