My wife has had very good luck with VERUS HEALTHCARE LLC. They are part of the Competitive Bidding Program. They accept the Medicare-approved amount as payment in full for all claims for the category. They were on the Medicare list when I put in my zip code even though they are 700 miles away. They also handle our secondary insurance, Tricare for life.
Everything was done by phone or email and promptly and they followed up with the doctor. We sent them by email a copy of the sleep study, the doctor's office notes and the prescription. They handled everything else. There was one hold-up. They needed a signature on the prescription and not simply the words that it was "e-signed". They sent the doctor their form with the info for him to sign, he didn't want to sign their form, so he re-wrote the prescription, signed and faxed it back. Verus overnighted my wife's PRS1 560 and the tap-pap and heated humidifier and modem. They use recorded phone lines and have been very courteous and helpful.
I now get my supplies from them also. They have been very responsive. For us, it has been excellent service; however, you don't have someone come out to your house and "fit you" or explain the equipment. They do have respiratory therapists but neither of us have had a need to seek their advice - so I can't comment on that aspect of their support. However, based on their other dealings, I would expect it to be good.
There is one other thing that I have learned about Medicare funding requirements. For the DME to get paid by Medicare, the prescription must be written by an individual enrolled in the Provider Enrollment Chain and Ownership System (PECOS). In other words, if a physician does not have an approved enrollment record in PECOS, Medicare will not pay for home health services provided to that physician's patients.