We hired Barry and his team to install 2 full-length glass inserts. They were really great. For example:
Responsive - When we were deciding whether to do the project, they were very fast to respond to questions by email. They were happy to quote based on photos/measurements and without any hassle. Emails were very concise.
Efficient inserts - What a pane sells windows to your specifications. We got high-efficiency triple pane with argon and low-e. You cannot buy those online or at any retailer. [As an aside, next time I would specify multiple panes with low-e to get the highest efficiency, not just one, which would make them a bit more efficient.] If you are putting a big window in, it makes tons of sense to get efficient ones.
Custom sizing - I got windows fit to my door. Some doors (like mine) will not work with the inserts you buy at a retailer.
Fast, clean, & quality - The install was fast and clean. All the garbage was taken away. If I had done it, it would have been a bunch of work to get the materials, do the project, and remove the waste.
Good price - I do lots of things myself but in this case it was well worth it to pay someone else. We put large clear glass in, transforming the door to a full-width glass door to let in light. Compared to the cost of installing an entirely new door, the inserts were about 1/4 the price (and would have been less if we didn't need a custom size).