How much do you weight, and what times are you trying to run? What characteristics do you want in a shoe (weight, cushion, fit, etc)? I'm going to assume you're a neutral runner based on your training shoes.
The Adios will work for anything from 10 km to the marathon. It's perfect for the half. I found myself wishing for a bit more cushioning in the last few miles of the one marathon I've run in the Adios.
I use the Boston as a daily trainer, so I still do a fair amount of fast running in them. It would work for a 10 km, but I'd prefer to have a lighter shoe for something that short. I'd definitely wear the Bostons if I had to race a marathon again. They have more cushion than the Adios and are a bit roomier in the forefoot.
One thing to keep in mind, I had to size up half a size from Nike to Adidas. I'm an 11 in Nike and an 11.5 in Adidas. The Boost cushioning is what sold me on Adidas. From the first few steps in the Adios, I was like "Wow, these shoes are amazing!" I hadn't experienced that feeling when putting on new shoes in a long time. They're fast, responsive, and they'll last you many miles.