The ALR is a great bike, so nice that Trek dropped the "S" Carbon and only offers the SL and SLR.
When i got back into cycling I bought a Madone 4 which was in the $2200 price range (2011). It has 400 level carbon while the Emonda SL has 500 level. It was a great bike and really was everything i wanted or needed. The only reason I replaced it was to treat myself after my last child was off the family payroll.
I replaced it with a Emonda SLR with Sram eTap.... AWESOME bike. I do spend some time in Scottsdale over the winter and rent a Emonda SL7 (Ultegra) and can tell you it's almost as nice as the SLR at 1/3 the price. It's the same SL frame as the SL5.
Anyway a SL5 with 105 is a great bike and well worth the extra cash.