When looking at price for DIY vs manufactured, don't forget that many of the newer fixtures available now come with the sort of controllability & software that is beyond the ability of the average DIYer. There's a big difference between what can be achieved with dimmable drivers as opposed to software that is able to mix colours, follow moon cycle & other bells & whistles. If you have an aquarium controller you can achieve some of these functions with a DIY build as well, but then you really need to include the controller in the price. It's tough to quantify bang for buck in LEDs these days.