DTR Laser are great to deal with. We have been dealing with them for a number of years now and they are very reliable.
Something to keep in mind with laser diodes is that more wattage does not always translate to better cutting. Unlike CO2 lasers, diodes tend to produce a rectangular shaped beam. It seems that increases in power tend to increase the anamorphic nature of the laser beam shape. This means that without the right lens focusing that irregular shape, you can often end up with worse performance with higher wattage diodes.
So far we have found the NDB7A75 to be the best balance between power and ‘focusability’. It doesn’t have the grunt of the of the NUBM diodes as mentioned above but can work very well with a standard 3 element glass lens.