Decent value, but not the best cheap Squier
I am huge fan of Squier guitars, and own a variety of entry-level Squiers that I play in both stock and modded forms. The reason for my 4-star review of the Affinity is that while it's a very good budget guitar, it isn't notably better from the Bullet or SE (which comes in the Strat pack with the amp).
The primary difference between an Affinity and a traditional Stratocaster comes in the thinner body profile and the cheaper components used to keep the price down. The tuners and saddles actually aren't bad. The stock ceramics are a little thin and underpowered, but can still sound pretty darn good. The neck has thinner profile than some other Strats, but players with smaller hands might even prefer that.
Overall, it's a great value that can be made even better with some upgraded electronics, pickups, and perhaps a $10 TUSQ nut. But, in my opinion, the Squier SE (Student Edition) has much better "bones" for an instrument that will play great and last for a long time. You can find used Squier Bullets, Affinitys, and SE's all over the place, but if you're buying new, you could certainly do worse than an Affinity from Sweetwater (and they do offer a variety of nice colors).