Get the new one with the matching bottom bracket.

The choice between a standard (53/39) and a compact (50/34) depends on how much climbing you do and how fast you are on the flats. Since most cassettes these days start with a 12 or even 11T small cog, you have to be very strong to be undergeared with a 50x12 or 50x11 high gear so the compact is more versatile and will let you run a close ratio cassette while still keeping an adequate low gear.