Looking to buy led's but questions...

So i seen that there are several brands names and designs available and i know everyone has an opinion so let here them. Lets say im going to have a 3'x3' area and have around 4 girls. Id like to know about are...

What size or power will i need?

Spectrums- can you use just one panel for a full grow when you buy one that has multiple 5-7 spectrums and just change the light cycle like any other light or do I still need to buy 2 panels a flowering and vegetation?

Brands or designs- tell me your experience and with what led set up?

Thanks

Get the best panel you can afford, it will definitely veg and flower. LED's are a get what you pay for type thing. As for what brand, try to stay away from the no name panels on ebay and get something from a reputable supplier. If you have a model in mind, search for a grow journal to see how other users like it. If you can't find any results, maybe that is one to stay away from. Just my opinions...