After a couple days of driving on them I'm pretty pleased overall, at least initially. Assuming there's another 10k of extra life in them compared to the OEM set, the grip trade-off is worth it to me. They're quieter than OEM (more especially compared to my tread-less OEM set) and a bit more compliant when going over expansion joints and road reflectors; it doesn't sound like the suspension is crashing over every bit of road difference. There definitely is a noticeable amount of traction given up, but I expect that to improve slightly as I get some mileage on them and I wouldn't consider it a 'huge' amount-it's noticeable, but still fun.
You'll be hard-pressed to find a set of tires with the same amount of grip at a lower cost and with longer tire life than the OEM set. It's a trade-off, so you need to figure out what is the most important to you. I commute over 70 miles a day and was more than willing to sacrifice some grip for longevity and comfort, especially when considering the cost, but I wouldn't expect this tire to stand out excessively in any particular way over the competition. There are tires with better traction, tires with longer life, tires with more comfort...but I think this set is going to do well-enough for me considering the price-point.
I think I'll probably go with a Max Performance tire for the FoST because it's driven a decent amount harder, but I don't really see myself going above the UHP's for the FiST as a daily driver, and there are significantly more options at the FoST tire size. This is also just a first impression with very little actual mileage, I could find this set to be significantly better or worse over time. My two-day opinion is not bad in the slightest, and I've had tires on other cars that I had already regretted purchasing within that short of a timeframe...