Electronic pH monitors in my opinion are nice to have.
I'd consider them pretty far down the list as "gotta haves" but still nice none the less.
I use an industrial unit from work, that costs around $1,500.00 bucks.
Over kill for sure - but it's an old demo unit I got cheap.
I've found that using an electronic instrument is nice because it does give me an instant reading, and it's interesting to see the natural pH swings that occur in most of our tanks during a 24 hour period. This can be done with test kits, but it's time consuming and you burn through a lot of tests in one day.
I test my water on the weekends, and if I get a reading using Salifert of FasTest that says it's 8.2 - that's cool with me.
The reading on the electronic unit may read 8.24 - but I gain very little from knowing the pH 2 places right of the decimal point.
They are handy for sure - no doubt about it. Someday I may hook it up and have the digital display reading 24/7.
It's only as good as it's last calibration. If it's not calibrated often, or drifts due to electrode probe degradation - then you're better of using a test kit.
If I was in your shoes - for my money - I think I would concentrate on first investing in a two part calcium/alkalinity product like ESV B-Ionic, and a good set of test kits.
Get your water chemistry right - especially the pH and alk.
Using standard pH and alkalinity test kits would be fine for this.
The electronic unit is not going to solve the problem - buffers, alkalinity builders and water changes will though.
But if you got the cash - and want the toy - go for it !
