PB Blaster is extremely useful. If you plan to do more work on your vehicle in the future, especially stuff like suspension, it may be worth it to invest in an impact. An air impact will require a pretty decent compressor, but an electric will have some higher cost due to the battery (although you may be able to get one that uses batteries matching tools you already have).
The main issue with an impact is being tempted to force a bolt out without using any penetrating oil (like PB Blaster) and then snapping bolts off, leaving you with an even bigger problem...
Anyways, hope that helps.