Pros +

Maps well paced designed that provide a lot of variety for tight action pack infantry based battles

Team Play is much more important for killing enemies and wining games in general given us a true aspect of what this series is about

Cleaner Iron Sights on Weapons for a clearer view on targets & the field

Less weighting & swaying for a more lighter moment across the terrains and pulling up weapons

New and revised weapons with the return of the classic AK47 that have a much more solid firing feedback

Hit boxes fixed/updated for more accurate wider shots registering were you actual point & shoot

Vehicles that set the atmosphere for the era including a golf cart! and of course your Helicopters Tanks & Boats

All competitive game modes available for maps

Classic music soundtrack based off the era

Cons -

No independent level & rank stats outside of Bad Company 2

Not standalone like the successful Battlefield 1943

No Airplanes

Without a Veteran Rank some new players to the series may find the lack of variety when it comes to weapons

No reflex dot scopes of any kind for Assault Light Sub Machine Gun Types

Sub Machine Guns are not effective as they are in Bad Company 2 falling under the rules of Battlefield 1943

Players who were not fans of Medal of Honor may not like this expansion do some very miner similarities

No Onslaught Mode or Update to include the Vietnam Maps & Weapons

Can not carry over or use Vietnam Weapons into Bad Company 2

P.S. I know it's not a golf cart but that's what I call it

My favorite thing about the add-on, outside of all of the new content, is that the game actually plays like a shooter.  Shots register and there isn't some weird delay.  I play on the PC and while BC2 is fun, Vietnam feels a lot tighter as far as the mechanics and everything feel.  I am very happy with my purchase.

"The reflex sight was invented by John Arne Ingemund and patented on December 7, 1973."  The US began withdrawing from South Vietnam starting in 1973...