Well, Reach is still a well-rounded game. The game plays smoothly at a pace that isn't too fast or too slow, there are many different gametypes to choose from, an iteration of forge with some limitations that force Forgers on Reach to get creative with the options they have. You are rewarded for the time you put into the game, the armor system is both rank and cR based, not either or, and does not rely on the RNG system.
The DLC is now free and the game was featured at one point for 'Games with Gold'. The playlists are populated, the campaign being darker in comparison to the other Halo campaigns while also being your own Spartan is awesome. The lighting and FX in the game are good and allow for some nice screenshots, the weapon variety is nice, the Elite Armor is simply awesome (Save the Elite Generals). There is even a wide variety of medals you can earn for doing good that actually mean something, like Hammer Spree, Hail to the King, and Hell's Janitor (Not like 'Generic Kill', Assist, and Distraction in the newer iterations), so the medal system is proper and doesn't feel like 'everybody get's a trophy'.
The physics system is nice and at times amusing as well when a Revenant or Wraith goes flying across the map at lightspeed XD. Also the excessively cursing Elites are hilarious. The Skirmishers are also the painfully lovable subrace of jackals exclusive to this game. Halo: Reach is like a grand Italian Sub, jam packed full of goodies and condiments without being soggy or falling apart.