I have a 14 SL ISP and I really love it, but I have a 17 Advanced Pro disc coming any day now. I have been wanting disc brakes for years otherwise I would totally keep the SL. I did do an extended demo on the new bike and I can somewhat agree that it is a harsher ride, but the demo wasn't set up as nice as my current bike or the new bike will be, so it is hard to tell if the difference in ride was from the frame, ISP, my better wheels and tires, seat, or that I have carbon bars/stem (vs Alum on the demo). I am building the new one up somewhat custom so I will be able to better evaluate once I get it, but I will say to my surprise I was faster on a bunch of climbs on the demo despite it being 2lbs heavier than my SL.
I agree that the older frame is better looking too. The ISP wasn't a problem for me until now that I have to sell it. Since I am on the shorter side, the cut mast may come to haunt me on resale. I don't think I would do another ISP but if you are a taller rider it would be less of an issue. There is enough adjustment with the ISP mast topper and spacers to accommodate smaller changes that you may want to make from your shoes, etc.
If you like the looks of the older bike better, go for it, you will not go wrong. And the money you save can be put towards upgrades
Superb post thank
s. All noted. One thing to ask, can the 2014 SL take 25mm in the rear ? I note the brake bridge not an issue, but the gap inside the chain stay looks tight - not a deal breaker as I ride 23mm anyway but know 25mm is where its at.
Thanks again. The shop put the bike aside today and I am making a decision tomorrow. Interestingly the 17 SL1 has slipped by 7 odd weeks in the UK but never a pressing decision to buy that anyway.
I am a slow climber by the way, but realise a super stiff BB and HT will help.