I worked with riak pretty extensively in that time period. I'm in more or less the same boat. It had cool features, but they didn't make up for the overall kind of slow performance and limited feature-set.
(Admittedly, our use of riak was clearly a case of premature optimization: we didn't have anything like the scale to require an available data-store.)
As a technical evangelist for Basho, I would encourage sales prospects to think carefully about what they really needed. One of the problems trying to sell Riak is that, unless you know you need the availability it can offer at the scale it can support, you're probably better off choosing something with more features and less scale.
And, although clearly we're swimming in more data than ever, not all that many people have both massive data sets and a burning need to never lose any of it. A lot of data can be lossy without any real consequence.
(Admittedly, our use of riak was clearly a case of premature optimization: we didn't have anything like the scale to require an available data-store.)