One of the worst offenders was Win Communications out of Atlanta. Early on, we were a prime dealer of Walker/Win products in a large city 250 miles away. When the 100D was released, we were sent several CPUs with versions lettered like "M" or "S". All the others were versions "R1.2" or such.
When we needed tech support, it was learned that the lettered versions were "field test beta" products, aka FTBs. There were extra "goodies" packed in the eproms we had no control over that they wanted to see if they failed before releasing them to the generral market as "R2.x" CPUs. Several times on one unit we had engineers calling in from Japan who re-wrote the eproms under the direction of the code writers in Malaysia while the system was running! I couldn't believe that. That was more like an Alpha CPU, not even close to a Beta. But there is at least one "M" unit that is still plugging away in a very busy federal office, so not all were bad.
So, given the choice between a fairly well engineered product from Avaya that may have some performance issues found after widespread implementation and a company that sends Alpha products to you as an unwitting participant in a field test, I'll take the Avaya edge every time!