I disagree, the 45A is easily the best, most reliable, and most full-featured of any of the heads for the Beseler. They are dirt cheap compared to what they used to cost. Usually well under $200 on ebay, sometimes under $100. (they were $2600 new in the 80s-90s.) I have 6 of them, I use one and keep the rest for spares. Also have some spare tubes. The tubes last a good while, hundreds if not thousands of prints. I have printed at least 600 prints on the set of used tubes I am using now and haven't had to change any (though the blue one is getting a little slow).
not only is it a great color head, but as mentioned it's additive so the output for color enlarging is better than a subtractive head (more narrow-band light). It also has a great built-in color analyzer/meter that can auto-correct color balance, do automated ring-arounds, has options for programming various emulsions, and many other features.
They are not too hard to work on mechanically, and aside from the tubes, there's not much to wear out on them. Sometimes they have sticky buttons but that is easily fixed. I have all the manuals and service docs posted on line if anyone needs them.
-Ed