Watt wise they are all overkill, Doubt the currant one is even 200w

Mostly the same rules apply as if buying for a new PC.
You pay for what you get cheap rubbish PSU's aren't going to out put good clean voltages and you may have been better off with the original PSU.
All PSU's slowly go out of spec, although a 5-10 rear old ATX is still much younger then a AT power supply which is probably closer to the 25 years.

You'll want to double check how the power button works. These were part of the PSU in AT and not always compatible with replacements and sometimes you had to get creative.
Obviously modern PSU's have "useless" connectors for SATA, PCI-E, etc.
The most important consideration is old PC's use 5v rail a lot more then modern PC's and and such modern PSU's aren't designed for heavy 5v usage but if we are talking about a standard Pentium, spinning rust and optical drive and few cards any decent brand PSU should be ok.