I'm sorry, this whole thing seems like a pyramid scheme.
It's not a " Ponzi scheme" it's basically like an insurance company (it may be even better as they weed out alot of risk (but have additional - as Jews have more babies)) a Ponzi scheme needs the next guy to continue as they are supposably making money - which in actuality they are not, so they take the new guys money and use it as their "profit money.. insurance/sharing is (supposed to be) sustained by their current enrollment - they charge a premium based on risk and they pool that money and use it for everyones bills - they don't need a new enrolle to keep them afloat...
That being said - United Refuah keeps to their terms the question is what is their terms...
#1 They only pay 150-170% of the Medicare allowance which means if you go to a doctor and the doctor charges double that you will be stuck with the extra $$ for example you go to a doctor and the doctor charges 3k dollars and the Medicare allowance is only 1500 United Refuah will only pay out 80 percent of the 1500 you will owe 20 percent plus the 1500 dollars. So the question is will your doctor(s) give you a cash rate that equals the Medicare allowance? Many doctors do not have such an option they have one rate and unless you have insurance there are NO discounts - hence you will be stuck with a large bill! Also keep in mind a doctor may not even take you as a patient if you say "you don't have insurance only sharing" as they don't accept "self paying" patients. Hospital's will also not give you a good cash rate which would get you covered under the "Medicare allowance" unless you apply for and are eligible for "charity care" you can get stuck with huge bills from hospital's as I'm not sure they knock down the price otherwise...
If you have a baby there is a 1500 dollar fee it works different than an insurance company which has a deductible of 1500 - as United Refuahs fee only goes towards covered charges meaning towards the 80% they cover, unlike an insurance company where the deductible goes towards the copay too for example if you were to get a bill from a doctor for 1500 dollars and your insurance company has a 20% copay and 1500 dollar deductible, you would pay the 1500 bill and you have met your deductible. With United refuah after you pay the 1500 only 80% of the 1500 went towards your deductible as 20 percent they don't cover and you are still going to owe 300 dollars towrds your deductible! (It's a fee and not a deductible)
Also when you have a baby - with insurance, the doctor bills the insurance after the birth - as per their negotiation with the insurance company. So if you have a deductible it will only be used once. However, without any negotiation you will have bills in calendar year 1 and bills from the same doctor that go into calendar year 2 you will have to use your 1k dollar deductible twice for both calendar years!
Basically, United Refuah can be a great value (and there are even some added benefits compared to a regular insurance policy as you are basically eligible to see any doctor in the USA (I think) as long as they take you (you'll only be covered the Medicare allowance..) If you manage to find the right doctors and labs that will charge you their "allowed charges" and are eligible for "charity care" at hospital's you will do pretty good - it will definitely take work on your part...
But if you want to "keep your doctor" and choose which doctors you want to go to you may not have much coverage...