Basement Builders is a reno company that specializes in basement finishing/renovating - and it shows. They're very good at what they do, their picture portfolio shows they can do fancy basements with a wet-bar and home theatre, but we wanted plain/functional basement and they were able to do that for less than the 2 other quotes we had.
We had them renovate most of an 1,100 sq foot basement in about 9-10 weeks, with short notice. They did an office/bedroom, den/family room, bathroom, and closed off a storage room and the utility room. Everything looks great, very high quality work, and the subcontractors they use were all very professional. They've clearly done this many times: they have a well thought out process/contract/agreement form, they post signs at the door and lay down floor protector, arranged for us to pick lights, cabinets, paint, flooring, tile, etc at a minimum places (much appreciated!) and were clear about any extra costs. They arranged all inspections, cleaned up after themselves (we were able to move in even before the final vents were in place), walked us through the layout of the walls/electrical/lights/etc and were even able to arrange a dumpster when we couldn't get one on short notice so we could empty the basement.
There's a primary contact so you can ask questions or request changes, if you're unsure they are able to make solid recommendations because they've done this many times (several of their suggestions have already paid off). About the only suggestion I would have is: more regular updates, like maybe a weekly email or text saying "here's what we're doing this week..." as sometimes there were periods when no one was there; also when the initial completion date wasn't achievable the earlier we could be told the better (we'd hoped for 8 weeks) so we could make alternate plan. Overall we're very happy, we would use them again.