Hi Antonio. ADD or no ADD - that's a good question! I have the 2014 Travel Pack which I bought new at a discounted price in 2015. It has ADD and I love it - but I have not test ridden the Strada model to compare.
So, you will have to get some test rides and decide - I can't see why the base model wouldn't be as good as the TP model if you are a solo rider and don't want panniers (though you can fit a Givi rack system similar to the Rally model) or cruise control.
If you can afford to go new.....it reads like the Rally is the best and I'd be keen to get a 2015/2016 model just in case there have been any secret updates or production quality changes......though my 2014 model is fine, there have been some that aren't (not sure how many are Aprilia's fault or some other cause.....I don't judge, just reporting what I've read).
Make sure any used bike doesn't have a sooty exhaust, and all it's services are up to date.
And don't be afraid of high mileage - the bike gets better and better with more kilometers - I have 25,000kms up and it is heaps better now than at 13,000kms.....
ps hop over onto the 2014-2016 forum and you'll find lots of photos, advice, experiences (good and bad and self inflicted) - this forum was started for the 2013 model and only a few diehards drop in to see if anyone needs any info......cheers from Australia!