I always thought both 145 & 146 had identical gearbox ratios. The 145 is definately the sporty one (better inside triming, upholtery etc). The larger boot space & 4 doors made it for me, although it was a tough choice. If I were single then maybe...I have had 3 146Ti's and 3 145 QV's and the 145 is marginally better to drive. It accelerates better as it has slightly shorter gearing and is lighter.
I also think the 145 looks better because of its design quirks, although this is open to debate.
Other than the gearing they are very similar to drive.