Welcome to the forums!
Take a look at the wavelengths of the two lasers (the XXXnm number)
447nm is a diode laser, which the diodes are sold in bulk after being mass produced and are relatively inexpensive, while the 473nm is a DPSS laser, which in short is an infrared laser at an insane power, focused and pointed at a crystal set that converts the light. This process requires extreme precision ($$$), not to mention the price of the crystal set alone. There's a pretty prominent color difference to my eyes, 447nm is a royal blue color, while 473nm is lighter and described as "powder blue".
Yes, you should get goggles for the laser. I don't personally own one, however you can expect a fairly bright royal blue colored laser, that is able to burn. Not many people start out with a blue laser, as long as you're not stupid it's a decent unit to start with. (Don't go shining it in peoples faces saying it's safe, it's not, I'm sure a lot of people are going to lecture you about safety so I'll leave that to them)