I love them all, but from a collector's standpoint it would have to be Rexair, Air-Way, and Hoover (from the old days, not since Hoover has become just another cheap vacuum). I bought a Model B Rexair at age 9 in 1957. By 1958 I had met the Denver, CO Rexair Branch Manager (later among the first independent distributors), the late Harold Mench and Mrs. Mench. I hung out at the Rexair office as much as I could get away with, and by age 14 in 1961 was doing all their repair work. Now, both Mr. and Mrs. Mench, who didn't yet know one another, were hired by T. Russ Hill, founder and original President of Rexair, in the Spring of 1937. The first machine had been sold in November of 1936. I learned an enormous amount about the early history of the machine and the company from the Menches, so, I believe, I am the Club's Rexair expert. I have recently volunteered my services to Customer Service at Rexair, to correct the many errors on their website regarding the old models. (For example, they erroneously illustrate the Model C, from 1950-55 as the original Series A Rexair built 1936-1940.) Customer Service is excited about this project, but have expressed concerned that top management won't care, as it has no effect on the sale of new units.