Does anyone have any recommendations for a pH meter for wine/beer?  I would prefer digital but if strips are more accurate or significantly cheaper I'm willing to go that route instead.

Personally, those $40 digital ones on Amazon are good for about 2 months worth of use.  I use a $1400 meter at work, but I'm assuming you don't want to spend that much?  I'd use strips and get a few different ranges.  What pH will you be looking for?  5.0 or so?  Get one that ranges like 3.5 to 7.5 or something.  Not 0-14.  Those strips will stink.

Sounds like strips are my best option, then.  It's been difficult to keep fermentation going in some Vintners Best fruit wine concentrates.  Reviews on line said they might be too acidic for the yeast.  Tried some redneck chemistry with baking soda and we were back in business.  Being able to test and adjust should be a bit more consistent.

In my experience, strips are good for ball-parking pH, but they do go bad after a while.  I am in the South, so humidity is a big issue with them.  I have used meters, and still mainly do.  Regardless of using cheap china junk to expensive lab grade meters; they all need constant calibrating.  I'd recommend a middle of the road meter and a pack of calibrating packets.

Edit: Sounds like you are getting a pH crash with too fast of a fermentation.  There are buffering agents you can condition your water with to help stop this.  They can affect taste, though, so it does take some experimentation.

I was barely getting fermentation to start in the first place.  Apparently this is a fairly common complaint with certain fruit wine concentrates from this particular supplier.  Hitting a small sample with a baking soda slurry caused a very strong reaction, indicating the need for proper ways to test pH.  A bit of buffering and we were able to get fermentation going.  I tend to fly by the seat of my pants rather than try to scientifically control for every variable.  Haven't ruined a batch yet, but this hobby is only about a year old for me.