HP does make some great, high quality business printers, but I believe HP was the first company to implement expiration dates for certain ink cartridges [http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01764161&cc=us&dlc=en&lc=en] , and that is a serious dick move.
I've never used a portable printer, but I believe the best contenders (i.e. nothing over $200) are the Canon Pixma iP100 [http://www.amazon.com/Canon-PIXMA-iP100-Mobile-Printer/dp/B0012W9APQ/ref=cm_cr_pr_product_top] and the HP Officejet 100 [http://www.amazon.com/HP-Officejet-100-Mobile-Printer/dp/B004TGHIS8/ref=cm_cr_pr_product_top].
The Canon doesn't ship with a battery (optional), so it's cheaper than the HP, which comes with a battery by default. Both batteries are removable and charge by connecting to the printer. However, the Canon power supply (external of course) is rated for anywhere between 120-240 volts while the HP is not. Bluetooth on the Canon is another optional purchase, while Bluetooth is built into the HP. Both units use separate black and tri-color ink cartidges.
I used to work for an HP partner, so every printer we had at multiple offices were HP, but those were all monochrome, business class laser machines which could utilize maintenance kits and replacement rollers. We kept using certain HP printers that were discontinued because there were no equivalent models with the same features. HP is notorious for dropping dozens of models in everything they make, every year.