We're in the final stages of designing our new home and would like to create a very open main floor with exposed beams and joists.  We had initially planned on Douglas Fir but after doing a bit of research came across the Parallam PSL engineered products.  They are easily available for us, presumably cheaper and provide a more contemporary look that fits our design better.

According to the product literature, the PSL beams can be sanded and stained.  We would then create a slightly dropped ceiling with drywall between each PSL joist to allow space for electrical service.

Just wondering if anyone has any experience with exposed PSL joists and/or beams or any other advice in this area.  What about VOCs for this type of engineered lumber?

We have used PSL beams and their cousins many times over the last few years, but only a couple times have we left them exposed. My limited experience has, so far, been positive. Depending on the stain color, the obvious difference in appearance from solid sawn beams can be muted so that a casual observer will not immediately notice. Which is what most of my clients want.
As to the VOCs, I am not an expert. But from practical observation, I have noticed no odors normally associated with outgassing. You should be able to check with your supplier/manufacturer for MSDS information on the product of your choice.

I am not aware of any VOC's from PSL beams.  Two concerns that I do have that might have an impact on your project is that people will drill or notch the load-bearing beams without following instructions and that some polyurethane sealers will stink for months.

Some churches, in fact maybe a lot of them, have exposed stained laminated beams. Maybe you can see some around where you live. I'd say leave them exposed and stained, and if you decide they don't look that great paint them later.

I would prefer the look of gluelam engineered beams over those, because they are made from actual boards, not just wooden strands. I will be putting gluelams in my next house.

That being said, my current house has exposed Douglas fir beams that look absolutely beautiful. I don't have any stain or polyurethane on them so there is no chance of any VOC's. Only issue is they like to twist a bit as they dry, but in a properly designed system this should be minimized.