I've used them through the years but now mainly go with their subsidiary, Magcloud which is less expensive and fits what I do a bit better.
Blurb has lots of options for paper, binding, sizes. You can also use their book assembly software, but with limited typefaces and, when I used it last, no way to magnify the pages for tweaking and no way to fine-tune the text, I simply downloaded the templates and did things in InDesign which has much more robust tools. Magcloud offers fewer options for paper, sizes, binding, but the price is better. However, you'll need your own software to assemble your package and then generate a PDF for uploading.
Both have had discounts the past few months and I've used them to print a couple of short-run books for my own amusement and to prototype for later upload to Amazon's KDP. KDP is pretty cheap, but paper and binding choices is very basic, almost one-size-fits-all.
Of the three, Blurb seems the best, followed by Magcloud and finally KDP. IMO, they all meet the mark of adequacy though if you are picky, play around with Blurb. It's not offset and the ultimate quality, but IMO does a good job and in my 40 years dabbling in the printing trades, each year seems to get better, faster, easier and cheaper. Compared to direct digital printing I did in the 1990s with similar technology, even KDF is pretty good today and Blurb/Magcloud is more than fine.
If you have any experience with InDesign or other page composition programs, that's a plus when it comes to preparing your work for direct digital output. If you agonize over the slightest variation in color, this may not be for you. It's pleasing color and reasonably priced, rather than high-end and calibrated to the n-th degree.