The system has a decent amount of internal room for a USFF PC. The top of the case pops open by pushing a blue tab on the back panel, and the whole chassis opens clamshell-style to present the system's compact motherboard. It has full-size optical and hard drives, but concedes to using SO-DIMM memory cards for upgrades (SO-DIMMs are more compact than full-sized DIMM cards, and share parts with your company's laptops). There's space and a slot for a PCI card, in case your business still uses specialized hardware that doesn't work with USB. Last but not least, there's an extra internal SATA port, so you could theoretically put in a SATA-to-eSATA adapter. The build quality feels rock solid, and the system hinges together so well that it's easy to service. These two qualities are rarely seen together on a business PC. USFF PCs have traditionally been difficult to service, thanks to the cramped quarters inside the chassis. The M91p is laid out so well that a simple replacement should take only seconds, and the more complex motherboard only a few minutes. Ease of serviceability should reduce downtime significantly.