Frankly, I'd like to compare the Pathfinder Beginner's Box at $30 USD to the D&D 5e Starter Set at $20 USD, just in case anyone is reading this thread and debating what to get. It seems like most of the people posting in this thread have been playing for a while. I'll try to be as objective as possible, so let me get my subjective opinion out of the way: the PFRPG BB is a better buy, the PFRPG is a better game, and nothing I've seen of D&D 5e has changed my mind despite my best efforts to give it a fair shake.
System: The D&D SS is meant to work for the D&D 5e ruleset. This is a new edition which will be out this fall in full. The PFRPG BB is meant to work with the Pathfinder RPG. D&D 5e looks to be very mechanically sound at the cost of offering a fraction of Pathfinder's customization.
Player options: The 5e boxed set gives you a quintet of pregen characters to pick from. The PFRPG BB gives you a quartet of pregen characters and dedicates a whole 68 page book to making and improving PCs. The online support from Paizo includes a fifth pregen. The 5e set has generic pregens. The PFRPG pregens are Paizo's iconic characters for the Fighter, Rogue, Wizard, and Cleric.
Replayability: The D&D SS has a single adventure which I won't spoil. The PFRPG BB has a similar adventure in it. Both are honestly pretty generic. Paizo offer more free adventures on their website. More importantly, it has an abridged list of magical items, monsters, and spells to take the party all the way to fifth level. The PFRPG box explains how terrain, settlements, and so forth work in order to help a novice GM continue the game past the first session. D&D offers their core ruleset online as a PDF for free. D&D Basic Rules Online PDF [http://www.wizards.com/dnd/Article.aspx?x=dnd/basicrules]. Paizo offers their full ruleset online for free. Paizo System Reference Document [http://paizo.com/prd/] Paizo operates on the OpenOGL, an old agreement which allows third party developers (like Paizo!) to develop for what was once D&D. Thus, Paizo has a lot of third-party supplementation of their game.
Layout and Appearance: The 5e box has less art, which is all in the same art direction as the 4e art - earth tones, angular characters, . The Beginner's Box has a lot of Paizo's pulpy, bright style. The D&D SS offers an abridged version of the rules in one 32 page book and a starter adventure module in another 64 page book. The PFRPG contains three books: a 68 page book for detailing heroes, a 100 page book on GMing and building your own adventures as a novice GM, and a 16 page novice little run through a maze.
Long Term Value: Both boxed sets come with a full set of dice. The PFRPG boxed set comes with a bonus flip mat and a large number of tokens with standies that can be used for the rest of your gaming career. Simply put, you can pay $20 USD for the D&D SS to play it once, or you can play for months with just the content of the PFRPG BB and then continue using a lot of its pieces for years to come.
Price: $20 USD for the D&D SS. $30 USD for the PFRPG BB. Free goodies are currently available at Paizo.com.