Thoughts on joining Healthcare Exchange

Looking for some advice. I have a healthcare plan that's pretty decent overall, but has gotten insanely expensive. Over $400 a month premiums now, and I'm a millennial. This plan isn't part of the ACA, it was an older plan grandfathered in.

I can get a plan on the healthcare exchange for less than $200 a month. The downside is, it's an HMO instead of PPO that I have now, and it has higher max out of pocket costs (although it's a lower deductible.)

Is it worth moving onto the exchange if I can get a cheaper premium? I've had my current plan so long it makes me nervous to jump into the ACA options, but over 400 a month is a lot and goes up every year.