Best BBT thermometers?

First, sorry if this is the wrong group to post this in. I'm new to this.

Second, I would like to hear from you ladies that chart your bbt. What thermometer have you been using? What are your likes/dislikes about that thermometer? What thermometer do you recommend? I'm really interested in finding out the best of the best. I'm 31 TTC #2 and thinking about switching brands. Tia