At least on 868 MHz, if you stick to the 1% duty cycle limitations that the ISM band allows, I doubt that you'll be happy with the web surfing performance.
This may be an EU duty cycle vs US time per channel thing? In the US you can frequency hop to get higher performance (the limit here is no more than 400ms per 20s per channel), which seems more aggressive than the 1% power sub-band EU rule (but ianal and I haven't read the EU rules carefully).