It's a different kind of smooth though. Yes it is very smooth once worn in, but the impact has a very robust and stout type of feel to it. Very distinct indexing through the bolt stroke, just very mechanical, kind of no frills sort of smooth.
Being a TL3 fan - I initially really did not love my impact. (I still prefer my tl3s over the impact). The first month of impact ownership was ehh yeah it's pretty nice... But as it's worked in, it has definitely grown on me. The bolt lift or perceived bolt lift is heavier compared to the TL3, and when you look at the bolts, it makes mechanical sense based on the cocking ramps and the cocking recess. Part of my break in process to get the impact to feel more like the TL3 was milling some of the proud edges on the cocking recess so that there is less of a distinct catch when running the bolt. (obviously there is a fine line of improving ergonomics and reliability).
Part of the reason the TL3s are so damn smooth- is they purposefully allocate a portion of the bolt stroke to cock on close. (Remember when Ted from ARC had two different mausenfield options?). And that is part of what I have come to enjoy when running a bolt. So not only are you having to work against a lighter 21 lbs spring (per bighorn) versus a 24 lbs. spring (per streater), but it also has a much more shallow cocking ramp to travel. This resulted (based on my tl3s) something in the neighborhood of 190 thou firing pin fall compared to the 'standard' of .220-.240. The bighorn engineers are extremely smart in my opinion, because (I'm not sure if on purpose) they have challenged just about every feature of a standard action.
Contrast that with the impact - 24 lbs spring, 220 thou firing pin fall (with my action), standard feature set - ejector, push feed, etc. All sums up tates' explanation of his action- "yeah, my shit just works'. And yeah that is exactly how I feel about it too.