ivi_yak,
The TDS5104 is good value if you need 1GHz BW and don't mind the clunky UI. It's fine for offline data analysis, you can export waveforms to file or program against GPIB. The built-in capabilities are very limited, however. The software is stable and doesn't glitch.
Flash drives are supported, the scope contains a regular PC motherboard and runs Windows 2000 or ME. The USB ports are hard to reach, so I prefer LAN connection for file transfer instead.
Part availability is on par with modern equipment, the custom hardware is difficult to replace indeed. The good news is that it's rarely a problem and will be obvious from SPC and self-test results. Any issues tend to be with the PC motherboard, the hard drive, or the power supply, all of which are commonly available or otherwise easy to deal with. Upgrades are possible, with some caveats, but not really worthwhile.