I'd be careful - it depends on what volumes you put through. We have 4 C8000's here (and a further 6 at another site) and I'm not a fan of their [lack of] reliability. The quality is nice, but the colours don't hold for a decent run and be prepared to have a tech around a fair bit. I'm very much a fan of the Ricohs. At my previous job we had a 901 and a 751 (also a KM C8000 and C6501) and the Ricohs left the Konicas in the dust in terms of speed and reliability. The Ricohs did about 75% of the colour work for that reason alone. The colours weren't as punchy though, depends on what you are after.
Make sure your local tech knows his/her stuff and is experienced in servicing the c8000s.
All of that being said, the C8000 is a huge step of from a 6501 in terms of quality.
If you can stretch it, look at the KM 1100 - we had one installed recently and so far it seems considerably better than the 8000s.