I have a 100, 5.5 and 5 (the last version set up with plus tires). I used to own a 4.5 that was my very first Yeti. I usually use the 5.5 or 5 as an every day rider and race the 100. The 5.5 is absolutely amazing and super fun to ride. It is a great climber and super fun when you go down. When you ride your 100, you will really appreciate the stiffness and pedaling efficiency. You will miss the fun of the 5.5. They compliment each other very well. What I did notice is the newer models (100,130 and 150) seem to have a few issues with bottom bracket height (too low) and issues with flex in the rear. I love the 100 for what it was intended to do but owning the 5.5 for 4 years, it rarely has an issue with creaking or anything. It may not be the latest but it is an amazing bike. If you can get a great component package and good wheels for a good price, you won't be disappointed. Plus, you will be a stronger pedaler on your 100 after riding the 5.5 all the time. I'm sure the 130 would be great too.