Positive experience overall. But be wary of the exchange/return deadline.
[Intial review. See below for update] -- Several months after receiving a subscription order (in which I was sent double the number of filters I'd ordered) we had to replace our heat pump. The filters, all as yet unopened, would no longer work for our system. I offered to return all the filters (again, two full unopened boxes) for a single less expensive set. I was told that under no circumstances could they flex on their return/exchange date — as if it were a law written into the fabric of the universe! Instead, as I pointed out, it's just a matter of bad customer service. Sadly, they didn't seem to understand this. I would not recommend working with them. UPDATE: Shortly after my call with CS and posting this review, they called me back. Since I'd been with them for 4 years as a subscriber, they wanted to make things right. I appreciate this. But do be warned that, when you speak to CS agents, they are instructed to be very inflexible about exchanges, etc.