BB7's can be hard to align, the cones are a PITA. I also feel like the BB7 pads don't center well at times they seem "canted". I don't dislike BB7's, I have used them for many years; I still have a set in use while I wait for another set of Spykes to arrive, and until the TRP brakes the BB7's the better mechanicals if that was your bent.
The Spykes are a high quality mechanical brake, whereas BB7's are a "price break" component, the difference in fit and finish, function, all are why the Spyke/Spyre are so much more expensive.
The Spyke?Spyre are better than BB7's because they are smoother, easier to adjust, lower profile, and higher quality.
In the end, however, all brakes are simply mechanical devices that apply force to compress the brake pads against the rotors, so they are only as good as the pads and rotor. So picking a good quality rotor (I like Hope Floaters) and using the correct pad for your application (Metal, Semi Metallic, or Organic). The Spyke and Spyre use Shimano pads.
I prefer mechanicals over hydraulics because they have more feel and adjustability, they are also tougher and more easilly repaired on the fly/trail. Many people feel that mechanicals are second class brakes, but in contrast to some of the hydraulics I have used as of late (Magura, Shimano, Avid, Formula), I don't really think any of the new brakes are all that, though Shimano has done a good job on their most recent brakes (M series) and the new SRAM (AVID replacement) is getting good reviews.
The only "new" thing out there is the four piston brakes that use larger pads, such as the new Magura. A larger pad is going to provide more stopping power, but it will also increase friction and heat up faster.
Honestly, what we really need is a high powered braking system that use carbon pads and carbon discs... or we need really burly rotors and brakes that don't overheat (heavy!).