Conclusion: The Z420 is priced fairly for the level of validation and support HP pours into its offering, and this is really where the system makes sense: moderate-demand visual computing for a low- to moderate-range budget. If you're really serious about graphics performance, look higher up HP's stack to the Z620 or Z820. But if you're seeking dependability and support backed by decent speed, then the Z420 is a great fit.
Pros: Potent performance, SSD plus hard drive storage, Plenty of expansion slots
Cons: No Thunderbolt or eSATA ports, Consumer- rather than industrial-grade hard drive
Excerpt: The HP Z420 is a powerful, expandable workstation. It combines the power of a quad-core Intel Xeon processor with an Nvidia Quadro graphics to give you a powerhouse system that can grow along with your company.
Pros: Xeon power, Quadro graphics, Lots of expansion room, ISV Certifications, USB 3.0 on front and back, SSD C: drive with 1TB D: drive
Conclusion: HP has done a great job of filling this workstation with great components, but still keeping the price low. If you are looking for workstation for your office then I recommend you look at the HP Z line of workstations. With such a variety to choose from it will be easy to find one that fits perfectly with your needs.