I'm always surprised by those transformers stuck right in the case next to quite sensitive electronics. Apparently it's not an issue, but I wouldn't have thought so.
It's miles away from anything high impedance which is all right a the front of the unit. Tis fine.
I keep looking at the TTi 1604 but they are still expensive, and like you with the Tek 465, I like my HP A which is nice to use and also of course I have the Keithley 160 (nixie) and the only problem with that is it's only DC and 3.5 digits but so so accurate.
Right now I'm looking at an Iwatsu 100Mhz 4 channel scope, (they are really 2+2 channels with the extra channels only mv and 1v per division) as a suitable replacement for my Goldstar OS-9100D scope andA and all the spares my trusty 25Mhz Rapid Electronics one. The Iwatsu 100Mhz has cursors and other shit on it to compliment my Hitachi. May even sell my HP 1740A and all the spares I have for it as well if I win that 100Mhz one.
I found a SMM for the 1604 the other day. Has a PIC as the brains in it so not totally repairable if it goes pear shape. 1906 is a better deal. They are programmable and have standard parts, CPU, RAM, EPROM, SEEPROM in them. Also the earlier 1905 also, 6502 powered!
Iwatsu made some nice kit. I'm not sure why it wasn't as popular as some of the other stuff on the market. It was slightly cheaper and did the job just as well.