I was considering a 465/475 mainly because these are supposed to be more serviceable than the other Tek scopes.
I think the 465/475/465B have more custom parts than the 2235 but I would not consider that a factor to chose between them because the custom parts are pretty reliable. You have to go back to the 453/454 for something that uses all standard parts and then you will have to deal with a smaller CRT.
Servicing can be tricky on the 465/475 and 2235 just because of physical access. The 465M is *another* not 465 like the 465B with a very different physical design which may be easier to service although they look the same on the outside. Still, I would not wait for any of these once one at a reasonable price became available.
For what it is worth here are the rough groups these oscilloscopes can be divided into. They all have dual delayed sweep:
453 - 50 MHz Discrete
453A - 60 MHz Discrete
454 - 150 MHz Discrete
454A - 150 MHz Discrete
455 - 50 MHz Mixed Sweep High Reliability
465M - 100 MHz Mixed Sweep Military
465B - 100 MHz Alternate Sweep
468 - 100 MHz Alternate Sweep Digital Storage
These all have mixed sweep:
464 - 100 MHz Slow Analog Storage
465 - 100 MHz
466 - 100 MHz Fast Analog Storage
475 - 200 MHz
475A - 250 MHz
485 - 350 MHz
The 2-channel 22xx oscilloscopes have several series as well but I am not going to list them other than to say that the 2235 and mentioned 2230 are in the same series.
If you choose Tektronix, I recomand the 465B or the 2235.
The 465 does not have any advantages over a 475 - and the 475 has a higher bandwidth, which is important for some purposes.
The 465 is *not* a 465B (or 465M); they can be consider separate models with the 465B replacing the 465.
The 465B and 2235 support alternate sweep instead of mixed sweep on the 475. I have never found a good use for mixed sweep but apparently it is handy for working with analog video. Alternate sweep on the other hand is generally useful. If you have not used alternate and mixed sweep, then I doubt you will miss either.