hhnngg1 I agree with you to a certain point, if you have a casual bike then Sora is fine, but I don't think 7,500 miles is a lot of miles, even a Walmart Shimano groupset will last that long!

I do agree that the cassette is better because it's made of steel instead of titanium gears or carbon carrier material that wears out far faster like you find with Dura Ace. And I also agree that the cost of replacement parts are far cheaper which is why I went with 105 because the briftors for Dura Ace alone are around $600, whereas the 105 is only $210 (both prices are for the pair); and I don't think, after using both, that the Dura Ace is $400 better then the 105, it feels like maybe $25 to $50 dollars better!! And Ultegra feels the same as Dura Ace. Thus I would never buy a set of Dura Ace or Ultegra ($400 for the pair) integrated shifters. But I did test ride a bike with Tiagra (which is supposedly better then Sora) and personally I didn't like the feel of Tiagra, it felt cheap to me, But Sora is not much cheaper then 105, only about $50 for the integrated pair of levers, and the quality of the build and feel between the two is vastly different, not like the difference between 105 and Dura Ace.

Then I have a friend who is a bike mechanic, among other things, that told me to buy the 105 because it was made better then the lower end stuff and would last longer, and I wouldn't be able to tell the difference between it and the higher end stuff. His only recommendation for the bike I ended up getting was to swap the 105 rear derailleur for the Ultegra. Matthew at Adrenalin Bikes where I ordered my bike from confirmed this as well when I inquired about it (I never told Matthew that a friend recommended I do that swap). They both said that the Ultegra rear derailleur was built better then the 105 and especially lower end models, but that the difference between the 105 and Ultegra front derailleur was nothing and since the front doesn't get used as often it was far less critical to spend the money to go with Ultegra. And every where I've read on the internet said basically the same thing, so in my mind I had confirmation.

The entire 105 groupset is only $760 retail list whereas the Ultegra is about 55% more, whereas the Sora is only 24% less then 105. I don't think saving $150 by going with the Sora groupset vs 105 is worth it, whereas I do think it's worth saving $500 not to go to Ultegra. When I swapped the rear 105 derailleur for the Ultegra rear d I only paid another $30 to do so, I felt $30 was worth it.

Please note, that is just my opinion, not meant to be argumentative about me being right and you're not, or whether or not someone should go with Dura Ace vs 105 vs Sora etc, it was my perception when I use the various groupsets and the perceived value in it for me and only me.