The SS Hope Pro 2's have much better engagement compared to the standard Hope Pro 2, it is quite good (although noticeably less than a WI Trials freewheel, King, I9 or Hadley).
I have been considering King's for a build, but they just seem like a high maintenance hub. I've read so many reports, and witnessed friends experience it first hand, of the hubs constantly loosening up.
I'm in the planning stages of a new build and also looking to try something else other than the Hope's. I like them, but I already have 2 wheelsets using them and I want to try something else. The first decision I had to make was what style of hub I wanted. Splined cogs, or a freehweel. In the case of a freewheel, WI is a no brainer, connected to most likely a Phil or WI hub. Seeing though as it is going to be racey, the freewheel system does not exactly make for quick gear changes from race to race, so I decided that a cog system would be best.
I narrowed down my options to these (but secretly also wanted a set of nice looking silver hubs): Hadley, DT Swiss 240, Hope, King, I9. Also a pre-built wheel system was out of the question for me. This was my thought process:
Hadley - great engagement, a little heavier, black only, bolt-on (although I imagine maybe a conversion to QR is available), people with them seem to be really happy with them though.
Hope Pro 2 - Extensive use with these hubs, I like them, engagement could be quicker, weight is not bad, convertible to QR although requires an additional purchase (not QR out of the box), pawl springs are notorious for breaking (I've lost 4 or 5 myself, and many others on forums have reported similar experiences), decent colour options. Super easy to service.
DT Swiss 240 - Light, heard great things about the reliability of the Hugi star ratchet system, big downside for me was the SS version only comes as centrelock, and that requires an additional adapter for the 6-bolt brakes I plan to use (you start deviating away from the "240ness" of the hub with these addons). Black only, but still nice looking IMO.
King - Look great, great engagement, lots of colours...but I've seen/read about these hubs constantly loosening up, would be open to hearing more experiences however. Low maintenance hub would be ideal for an SS, and the idea of constantly having to check on the preload I think would be super annoying. Perhaps too many expensive and unobtainable (for me) tools to do my own service on them.
I9 - I'm referring to their classic j-bend spoke hubs, not for use with their proprietary spoke system. Great engagement, colours to choose from, also look great. I've read that much like the Hope's they are easily serviceable without crazy tools. Lighter than kings, and with more engagement. I know quite a few people with their complete wheelsets who have had great luck with their hubs. The idea of using classic readily spokes appeals to me.
As of now I am leaning to I9, looking forward to what others have to say. Hope this helps!