If you look at the Big List of Mobile Processors (CPU Benchmarks)
you'll find the i5-2430M ranked @ #44 and the A8-3500M ranked #136.
The AMD A8-3500M quad core APU
trades some CPU horsepower to get a better graphics option - Radeon HD 6620G - on the APU package. Still, a capable performer and worthy of consideration if you get a very good price break over the i5 models.
For a business class multi-tasking workload I would go with the Intel Core i5-2430M
. That HD 3000 Graphics
on the CPU is roughly equivalent to a Radeon HD 5450 or Geforce 310 dedicated graphics card from a couple years back.