The channel selector issue is a concern because replacements are no longer available. If you end up with a 201A that has a bad selector it will require some creative engineering to devise a work around.
Most everyone who ever had a Tram opened up the VFO for transmit. Doing so took a lot of strain off of the channel selector as it was no longer necessary to change channels- unless you wanted to expand the range of the VFO.
They can and do sound excellent on SSB but there is a catch: The VFO is going to drift, and drift a lot. Mine has an issue with the TX and RX frequencies being about 100Hz out of sync. My personal tech is a retired broadcast engineer with a room full of test gear and he couldn't get it right. I sent it to Greg Barkett and HE couldn't get it right. I've spent over $500 in parts, labor and shipping (they are quite heavy and expensive to ship) and it's still not quite what it should be. Research on the Tram forums state that even when new the VFO wasn't all that good. A look inside any Tram confirms that it's quite obvious that the VFO was never designed for transmit.
Over on the crystal side of things they are much more stable but remember that these radios are 40 years old now and those crystals have likely wandered a bit themselves. There are trimmers inside that can bring them back to spec but it's a very touchy process.
Other issues include excessive heat- something to be expected in a tube radio. Tram, for whatever reason elected to put just a single tap on the output side of it's power transformer, requiring dropping resistors wherever lower voltage was necessary. All that unused voltage manifests itself as heat. The placement of some of the boards, particularly the BA board insures that over time they will become brittle and fail.
Many owners of these radios bypassed the dropping resistors on the PA final for more power. This produced more heat. A common cure was to install fans on the back of the unit but doing so aggravated the VFO drift problem.
To add to the previous posters- yes they do sound good. I love mine, but as a daily driver it's a bit impractical. It is for this reason that I have put mine into semi-retirement.
Radios of this caliber are a lot like a beautiful woman. They are rather demanding and high maintenance, but if you treat them right they will make you very happy.
If you choose to add one to your collection, buy the very best example that you can afford. Try to find one that has the original owner's manual and schematic. The manual has a complete parts list and alignment instructions- not to mention it's a hoot to read- whoever wrote it had a sense of humor!
Footnote: Although Greg Barkett is considered to be the guru of Trams and Brownings, I was less than satisfied with his work. On the plus side he did turn it around extremely quickly - less than a week. However he doesn't work cheap and although I sent him a detailed description of issues he did not not address all of them. When I called him about the VFO sync problem all he said was ' it's a tube oscillator, that's the way it is'. For what he charged I really wasn't expecting excuses. Not saying he isn't a good tech, i just expected more from him.
Good luck.