The Lexmark Pro 715 is not a bad multi-function inkjet, but the problem is that it's outclassed by Epson's WP-4535DWF, which has a similar asking price, yet is much faster and a good deal cheaper to run.
This printer is fast, cheap, and easy to use--too bad about its weak graphics print quality and high ink costs.
The Lexmark Platinum Pro 905 is a fully capable all-in-one business device, but its touch screen might throw a wrench in your workflow. The Smart Solutions widgets add virtual customization to the control panel, but we wish Lexmark had retained a few hard buttons as well. As the top dog in the Lexmark printer family, the Platinum Pro 905 does the job, but the HP Officejet Pro 8500 Wireless does it better.
The Lexmark T640 is a solid laser printer with convenient extras, security, and expandability features ideal for small-office workgroups.