I have had some extensive exposure with the diode laser, a CO2 laser, and some experience with the Hoya hard tissue laser. Before working with lasers, though, I used an electrosurgery unit and did not see the need for lasers. I thought the cost was prohibitive, as well.
I started using the Odyssey diode (on loan) about three years ago. After one month of use, I was sold on the technology, and put my electrosurge away. The most important thing to know is that the zone of necrosis is 50 microns with the diode laser, whereas it is about 500 microns with the electrosurge. Because of this and furthermore, when using an electrosurge, the patient requires profound anesthesia for tissues and teeth to remain comfortable, but soft tissue lasers are kinder and don’t cause the need for such anesthesia.
I recommend the diode laser to clean up tissues (hypertrophied tissues, overgrowth), for gingivectomies soft tissue re-contouring, and for troughing final impressions because the control is great.
More recently, I’ve used a CO2 laser, which is often used for flaps and larger procedures. Many of the new CO2s do well and are toned down. However, with the CO2, you aren’t in actual contact with the tissue as you are with a diode. I found that the Hoya hard tissue lasers are great for pedo and filling work. I do more crown and bridgework, so it’s not there yet for my needs. I find that I use the diode more, then the CO2 would be secondary.