Yes, by todays standards they are bulky and of modest performance, but had very good control, and just gave a nice deep hum instead of a high pitched whistle.
Their lack of a built in BEC was not a severe disadvantage. If kept within their limits, particularly voltage, they were solidly reliable. Because of the output transistors that had to be used needing a heavy current to drive them, the drive resistors were right on the edge of their power dissipating ability. Giving them just a bit more voltage caused them to cook both themselves and their surroundings.
But progress happened and the market preferred the resulting smaller, cheaper items with more abilities.
