I bought a Lorex - 4 camera system 2 BF's ago for a great deal. The NVR and 4 - 1080p cams for the price of just two of the cams.

2 years later ---- I've migrated over to Blue Iris and replaced the cams with better ones. If I'd known that 2 years ago, I would have done a home built with BI but it worked and I was happy for those two years so maybe it was just part of the learning curve...

Another lesson I learnt was to get all vari-focal or PTZ cams so that I can mount them and remotely adjust/view them without needing to get out the ladder. YMMV though, just my $0.02.

I have now a 12 cam system with BI, with a $600 25x zoom Dahua PTZ and the rest some cheap chinese 5x zoom PTZ with a smattering of dome varifocals and a couple turrets. Super happy with them - even the cheap $80 Chinese no-name PTZ's have been working fine.