Some info might help tailor answers. Have you owned a diesel before? What type of driving do you do...city or highway?
I had a VW TDI Jetta diesel, sold it back to VW and got a '14 Cruze diesel. Have been very happy so far. Better MPG, more fuel capacity, 17" wheels (vs 16 on VW), smoother ride, quieter.
One thing to be aware of, the Cruze diesel does NOT have a spare tire. The spare tire compartment houses the Diesel Emission Fluid (DEF) tank. To resolve that, there's a thread in this forum about getting a Buick Verano "donut" spare.
There are some slight cosmetic/appearance changes between the 2014 and 2015 models (I like the look of the 2015 better).