Good quality pens do work very well, and give more accurate results than comparator results, in the same way a good quality photometer gives more accurate results also.
I am not against it, in fact I have a medium price pen, but use it infrequently as I have a high quality photometer that does the job exceedingly well.
You will find with anything though we do try to recommend cheaper, cost effective methods of testing pool water (The TF100) for residential pool owners, there's no point in suggesting to newbies on the forum (or experts for that matter) that they should go out and buy expensive equipment when a TF100 is accurate and cost-effective for the majority of forum users in the residential pool owners audience.