User blog comment:CykeP/And Now I'm Torn/@comment-26192563-20151111080454

Personally I would say to go for Dex and Daina. While the Kagamine's do have more popularity (that's an understatement), keep in mind that their VP isn't a native English speaker. Considering CFM's history of attempts at quality English VBs, I personally don't have high expectations for Kagamine English.

Of course, demos for English aren't out yet, so I'll give them the benefit of doubt.

Dex and Daina on the other hand were made with a native English speaker, which will probably produce more realistic English results.

One thing you might need to consider is the vocal range and versatility. Based on demos of Dex and Daina and the songs I've heard the Kagamines in, I'd say that purchasing Dex and Daina would give you a more wide range while the Kagamines have a smaller range due to having the same VP. However, the Kagamines would be easier to harmonize.

In the end the decision is up to you, but if I were in your position I'd be leaning more towards Dex and Daina~