Bad booster?

Looks like there are rebuild kits...Found ones offered by Harmon Brakes.
Has anyone had experience using a "Harmon Classic Brakes" company brake booster rebuild kit for a 1967-69 a body (O.E. Mopar booster by Midland)?..

I am weighing the pros and cons of buying a rebuild kit vs having a specialty rebuild shop do it for me.

There is a shop in Portland, OR. called "Power Brake Booster Exchange". It is a 6 hour round trip drive but I am planning on driving it for another reason. Looks like there are some mixed reviews of their work in this thread...

Looks like the list price to have it done at the shop starts at around 170. if you have a core or to buy the rebuild kit would run me 225. so the shop appears to be the better value without having checked on what extra charges the shop may want to charge. (not to mention the diy work/time)