Your basically talking about the new emerging technology vs older more established technology. The B-series engines are still good engines and are very efficent. Standard VTEC is getting long in the tooth and even the GS-R head was design and based on technology was first introduced in 1994 (I have no idea when in Japan) so it's at least 10 years old. The B16A has been around since 88 I think? The K-series engines are much newer, have more advanced versions of the VTEC system along with VTC and more modern engineering and technology went into their design. That said, it's still relatively new and your not going to have the same resources or aftermarket that the B-series engines offer but in the end, you have more potential with the newer engine. Basically, like most things, it comes down to money. A K-series swap is going to be more expensive. The motor is more expensive, the parts are more expensive and the knowledge base isn't as extensive, but if your will to put in the money and the time, it's a worthwhile pursuit.

I don't know squat about K-series engines at this point and I don't know anybody in the forum with swap experience, but hopefully we'll all learn eventually. If you do decide to do the swap, keep up updated on your progress and share your experiences so we can all learn.