OEM struts fail. The Toyota struts in a new to me 2005 highlander w/191,000 miles were made by KYB and were shot. struts in a new to me 2000 Avalon with 126,000 by KYB were shot.
Looking at the FCS $50 quick struts I just got for both the Avalon and Highlander...I can't tell you i can see a difference between OEM and the FCS. Installed - I can't feel it. I put AM KYB quick struts - $150 each - in my 2006 Accord v6 years ago and they were new car stiff and took about 6 months to settle the right height. I like the Accord's ride and to me the extra $200 was worth it. Same with my 2003 4Runner. It has the XREAS shocks, but I put on KYBs. Stiff, as it should be.
Toyota cars handle like mush, and the FCSs are fine. I can replace them what?? 5 -6 times for that price compared to a OEM from Toyota. My labor is free.