Tires: tire quality, utqg rating, vw passat

Question
I had a tire blow out on me while driving home from vacation today.  My husband is worried that I was suckered into buying some crappy tires, and I was wondering how to compare the classifications.  I want to compare the new tires I bought to the ones that we had on the car originally.  First off, I drive a 2003 VW Passat.  The old and new tires are P195/65R15.  One of the main differences I noticed was that the old tires are 89H while the new tire is 89S.  I can not find anywhere what this means or what the differences are.  On one of the maufacturers websites it is the "LVSS" and the other is "service desc.".  I don't know what either of those stands for.  (I'm tire illiterate).  From what I found online, there is only one other big difference in the UTQG rating - the old tires are 300AA and the new is 440AB.(I also do not know what this meeans)  Is any of this something to worry about?  Or can you put my mind at ease and reassure me that I'm not a dummy? (the latter is prefferred).



Question 2:  Same car... we now have 3 different types of tires on the car (brands and slight differences as noted above).  3 fairly new tires and one old tire.  Is it bad for the vehicle to have all these different quality tires on it?  The two front tires are the same type and brand and are also the newwest.  The two back tires are different brands and maybe different types.  I read in your profile that you don't want to compare brands for customers.. but if that would help, I would be glad to drop the brand names and get your input there as well.  Thanks!

Answer
Sarah,

You should spend some time at Tire Rack's web site in the "Tire Tech" area.  The answers to all your questions are there.

But the short answer is the S is a speed rating and S is lower than H.

The UTQG indicates your new tires are better wearing, but lower speed capable (just as the speed rating indicates.)

Having different tires around the car tends to make the vehicle pivot around the odd tire in an emergency maneuver.  With 3 different tires, your car could be quite a handful.  
But I'm going to bet the tire failed as a result of a puncture, which has absolutely nothing to do with the quality of the tires.

But overall it doesn't sound like you are not doing a good job maintaining the safety aspect of your vehicle.  You should be rotating your tires so they wear at the same rate and that allows you to replace all 4 tires at the same time.  This results in a vehicle that will handle emergency maneuvers as safely as possible.