Some people do use them. I find then unnecessary. What troubles are you having with color matching?
If you do purchase, make sure it is a good brand. Myron L makes very high quality pH/TDS/ORP pen-style testers. Whatever brand you get, make sure you get at least a pH 7 and pH 10 calibration standard fluid (there's also a pH 4 standard). You should always verify that probe is properly calibrated and correctly working. They also typically need to be stored with the tip wetted by either a DI water solution or a DI + KCl solution.
I tried a couple of cheap ones, and to be even close to accurate you need to calibrate them almost every time you use them. It was more of a PIA than I wanted to deal with.
The pH test is the primary reason that I bought the LaMotte ColorQ. It gets a lot of bad press here, but it works well for me for everyday tests. I also have the TF100 that I use when accuracy is an issue or I want to measure FC above 10 ppm.
I've got a Milwaukee PH55 that sits in my cupboard and is going to end up in the trash one day. When I used it I had it in the storage solution, and needed to calibrate it every time I used it. I have far more confidence with phenol red and comparator. The trick for me was finding the best comparator for me. The BlueBlue devil works for me, with pool school I don't need the acid or base demand so I cut that side off and it fits nicely in my K-2006 box.
Thats different than any pH sensors Ive ever used. None have ever suggested storage in DI water, but in fact the opposite. Rinsing after cleaning is fine, but soaking for any significant period of time would not be. See the link to MyronL below stating just that. I dont think this instrument has technology different than the better ones like the MyronL, so I would double check the instructions. Based on my experience, a mfgr suggested cleaning process followed by a soak in 4.0 buffer usually has the best results when trying to revive a pH sensor or probe. I've done this more times than I can recall, and whether or not it works depends on how old and/or how well the probe has been cared for. If it were mine, I would avoid soaking it in DI water.
In my lab days, our high-end lab bench pH probes needed to be rinsed after use stored with the tip submerged in a plastic cap full of a saturated potassium chloride solution. This was to ensure that the silver-silver chloride electrode remained moist and that the solution inside the glass bulb tip always remained saturated with chloride ions.
I don't know pen style testers well enough but I guess they're designed differently from lab bench testers. But even our bench testers required regular calibration checks to ensure they were reporting accurate values. We used the probes daily (multiple times throughout the work day) so calibration was just part of the daily routine. Probes would last about 12-18 months before needing to be replaced.
"Pen" or other handheld types are really not too different at all versus bench types. Some probes for controllers Ive used are a little different in terms of salt bridge additons to the setup, but maintenance wise, bench and handheld probes usually require the same type of maintenance routines. All of them need pretty frequent calibration in my experience. A lot depends on what they are used to measure.
You can buy an acid demand regent for a couple of bucks and add a drop to the test. It will lower your Ph and the resulting color is generally easier to read. You can then reverse engineer using Pool math what your actual PH was before the addition of the acid demand regent.
^I would be concerned with the accuracy. I've never done it but I guess you could use the base and demand reagents to run through the colours to get an idea of what they look like. I found a comparator that works best for me. The Taylor one that came with my K-2006 has a printed colour range while the Blue Devil that I prefer has a series of coloured liquid filled chambers that you look through the same as the sample. The only down side is that the Blue Devil reagents aren't as good as the Taylor but I have it on good authority that I can use 4 drops of the Talor reagent in the BlueDevil comparator all is good.
The colours are ambiguous to us all in the begining but with time you do get used to it. I test regularly and the change is always the same, 7.6 - 7.8 which I can pick in an instant.
I have used "Oakton ecotestr pH2" testers for several years. Even with a lot of use (multiple pools and spas per day) I only calibrate them once a month which is very easy to do. I have to replace them after 1 to 1.5 years because of the high use, due the response becoming slow or needing more frequent calibration. I hate having to putz around with drops and color matching when I don't have to.
I would add that the only issue I've had was when I bought some pH probe cleaning solution. It really messed up my calibrations and I ended up throwing away those testers because they wouldn't stay calibrated.
I'm slightly color blind - as many men are - so the difficulty for me is not seeing that there are colors, but discerning between close shades. But since I'm really only trying to keep it between 7.2 and 7.8, there is enough difference there to see it. At first I was being too critical about was the reading EXACTLY 7.6 or 7.7. Now if it is more than 7.2 and less than 7.8, its good. It it isn't between those two I know which way to adjust. With a swg usually I simply add a 1/2 gallon of ma every other Sunday. NBD.