Would not wish to be without it. Makes a huge difference in terms of keeping control of the business. There are a number of alternatives. HOw they stack up depends a lot on how you would be using your database.
The reason LB wins hands down for me is that for a pittance a month I not only get free upgrades as they come along but also online sync. This means I have access to my contact database at home, on the studio computers and also my iPhone and iPad. Some other alternatives can be cheaper but you are limited to the one computer. They include:
fotoSF. I originally had the light version of this. Tried to be clever and run it from Dropbox. A word to the wise. Don't!! The full version is just too expensive unless you have a copy of filemaker already as you need that. The light version is quite cheap. Often free if you book one of the courses the designer runs on photography.
Spectra. This is the one used by the likes of Venture and is available free as single use on a single computer. GEts silly money very quickly once you start bolting on extras that come with the others though.
Studio Cloud. Currently free for single use. Again a lot extra if you want to use and sync on several machines. If you use Proselect this could be worth considering as the two now link in together.
All the above are aimed at general portrait/wedding photography. IF you work is stock or editorial then it may be worth looking at software dedicated to this area of work.
If you have any specific questions about LB just PM me.I've been using LB for a while now including the beta trial when they first moved it to Windows. Another thing I like is it has 'real' people behind it. LB is essentially Hamish and Tom who are very responsive to any problems. Several times I've pointed out some issue to have it corrected by an upgrade within a few days.