Giant and Trek are like Honda and Toyota of the bike world. They have very similar bikes. They have the best warranties and are very reliable bikes. Definatly only get a Trek bike from an authorized retailer. I think buying it at the shop is even better than buying it from Trek.com. This store is great because they not only sell trek bikes they have a maintenance shop too. And they have a trade in program.
Really it all depends on the rider and whats comfortable for you however trek stands by their frames for life so 30 years from now your frame cracks and theyll replace your bike with a current model.
Trek in the last few years has been releasing homerun after homerun. I would depending on the model that Trek is a bit superior. But you would need to clarify what type of bike youre looking at.
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