I use the Testo 330 and the Bacharach PCA3, they pretty much equal when it comes to features and responsiveness, the biggest difference is the cost of new sensors, the Bacharach O2 sensor sell for around $150, Testo $320, Bacharach CO sensor $280, Testo $850.
Testo quoted me around $1200 for the two sensors and calibration for my 330, I could buy a brand new analyzer with that kind of money! I would not buy anything Testo ever again!