BlueLab is probably the best I've used but they can be pricey. Usually around $100 for each meter but they last for a long time and are really accurate.
Just remember to take care of your meters too. Get the storage solution for the ph meter and put a few drops in the cap when you store the meter. I'm pretty sure they come with a 1 year warranty also. I've only had 1 go bad on me and the guy at the hydro store replaced it for me. At the last grow I worked at we treated our Bluelab meters like shit and they worked great.
I use the Blue Lab PH pen and EC Truncheon. Great meters and never had a problem with them. The only part I don’t like about the Truncheon is it won’t read below 200ppm.