Thanks... The Bosch emits hand-arm vibration levels of between 5 and 10m/s2... The FEIN seems to do between 2.5 and 15m/s2, depending on what accessory and oscillation setting you use.
Here's the important bit. If a tool does around 5m/s2, you should 1) use protective gear such as vibro dampening gloves, and 2) not use the tool for more than 60 minutes a day.
At 10m/s2, you shouldn't use it for more than 30 minutes a day, and you should most definatly use protective gear.
At about 15/s2, you mustn't use the tool for any more than 10-15 minutes a day, and certainly not more than 30 minutes a day.
The reason why is this: Nerve damage can occur from exposure to excessive vibrations, particularly frequent excessive vibration. I read about a guy who used a jackhammer every day for about 5 years, without even gloves, and the nerves in his hands got so damaged, they felt like, and behaved like, gelatinous lumps. He couldn't even grab a pencil.
That's an extreme case, but if one's not careful, arthritis or loss of sensation is quite possible.
Here's something I found for you brits:
Health and Safety Executive PDF on hand-arm vibrations