I have had nothing but OUTSTANDING service from SONA. I've sent in a total of 14 scopes over the last 6 years to have reticules changed (I need the #4 or #4A nowadays; Swarovski discontinued their #1 reticules a while ago] & EVERY single time I have had nothing but great service from them. They always do a complete check, service & argon purge at the same time at no additional charge.
This past fall I sent in an older scope (~1972) that had had the ocular housing & lenses crushed. The rebuilding cost was much less than a used Leupold. It came back with a new housing, new lenses, new seals, they also replaced the objective lens assembly; essentially a new ~$2,500 scope, for $350.00US.
The only downside is the wait to have them sent back to Austria (2-3 months), but only for the Kahles scopes. Everything else is serviced in Rhode Island, including the older steel-tube Habichts.
You set up an account, complete a service request, they email you a pre-paid Fedex label, you box it up, drop it off & they email you when the scope is received, then wait.
Granted, it's not free, but what in life of quality ever is!
There's another 3 scopes to be sent this fall to have the reticles changed to #4A's.
Putting my money where my mouth is, I sold my 3 S&B scopes given their lack of CS for a scope older than 25 years; Zeiss sucks the big one to have a reticle change-over (+$500), especially on a +25 y.o. scope. As a result, I now only own 1. Hensoldt is now owned by Airbus & they will not work on their older scopes [I now only own 1], leaving me with only one option for Alpha-class scopes. (Well, actually 2, but Kahles has been owned by Swarovski for a few years now)
Leupold CS is a joke. I phoned Korth to have a reticule change done on a VariX-II. They said based on the serial number it's too old. But they would give me $50 off the cost of a new one, however, it would not come with the reticule I wanted, so I would have to add the cost of the reticule change to the price of the scope, plus shipping.
Not too many years ago, Bushnell did reticule changes, but not any more. I don't think their Canadian Service department actually does any service work. Defective scope comes in, gets thrown into the garbage bin and a new Made in PRC scope gets sent out.