This doesn't answer for a drill press specifically, but is the method I use for choosing any major power tool purchase.
1) I determine the price range breakdowns for a given tool. You will see natural breaks in manufacturer pricing across a given variable. Often it is hobbyist, pro-sumer, proffesional, industrial or something like that. The size of the motor will usually be a key factor. Quality of key mechanics will also matter - such as bearings.
2) I identify 3 models in the price range I'm comfortable with. I do this by looking around on the web to see what other people suggest and so forth. Often tool round-ups on blogs or buying guides in woodworking publications work for this.
3) Next I make a chart of the specifications that seem pertinent to the tool and put this in a research document for my tool. Here is an example for a bandsaw purchase:
4) I then create a section in my research document for each model and start digging around on the web for more pros and cons. I list them under each models section with links.
5) I search for specific gripes on each tool of the 3 chosen. Some models of tools seem to be known for certain problems - some you can live with or not.
6) I look for any oddities with respect to repair or upkeep of the tool. If the tool has an oddball proprietary chuck or something, might be a no-go if you're hoping to run to a box store and buy replacements.
7) I check forums on the tools. Again documenting with links any issues or advantages.
8) I see if I can find the tool in a store. And I watch several videos of the tool in use.
9) Look for deals on the tool. Sometimes a tool needs to be shipped - but freight can be averted in the right circumstance. There's also the chance that it will go on sale at a certain time. I will contact sellers of the tool and specifically ask that question.
10) Buy the tool. Examine it when it arrives and make sure everything is functioning properly and there's no damage - contacting the seller immediately if there's any problems.