SRAM 10spd

Rival. Cheap as 105, lighter than Dura Ace.
Also the only SRAM group with 180 mm cranks available. Force and Red use carbon cranks and SRAM doesn’t make them in180 size, counting me out.

Clack. The shifting with SRAM is very mechanical, very positive, very loud - you can’t miss that you shifted. It is also very precise - perhaps because it is so mechanical. It is difficult to shift an extra sprocket.
Everything seems great. Brake levers are a pleasant shape. Hoods fit my hands and bars better than the Tiagra I had. Shift cables are hidden under the bar tape so it looks better. Derailleur adjustment is quite robust, rather than fussy.

At the same time I moved from pretty cheap Shimano cantilevers (even Shimano has upgraded these brakes since I bought them) to Avid Shorty Ultimates. Where were these brakes when I had cantilevers on my mountain bike? They are easy to set up, easy to adjust, well thought out, light, and just plain work. One finger braking. I could have set them up even more powerfully by lowering the cable hanger towards the tyre, but with mudguards I had to have them up higher (less powerful up high).

It might be my 8 year old bike, but it feels all new, looks different (silver Shimano bits replaced by black SRAM bits) and works better. I am ambivalent about the extra sprocket, however. I thought 7 was enough.