Sonus is an excellent QD for use with Klasse, however, it becomes rather pricey to use on a daily driver. The rims on my garage queen are Klassed, and I use the Sonus Acrylic Spritz on them in between and after washings with very nice results.
Once the weather breaks, and I can Klasse the rims on the daily driver, I will use the Sonus on them as well - I really like the performance of the Sonus over Klasse on the rims. I do not use Sonus on the finish of either vehicle as I find it difficult to spend $15.00 per bottle for a QD spray for a daily driver, and the Vette wears Souveran, which is incompatible with the Sonus. If you don't mind the price, Sonus is excellent.
If you are looking for something "over-the-counter" that is a bit more wallet friendly, my choice would be the Eagle One Wet Wipe&Shine. I just purchased 2 bottles of this yesterday for use on the finish of my daily driver.
My opinion of Meguiar's FI.....don't waste your money.