Which one is generally better? I know Pedros is more environmentally friendly.

Pedro's does some better, others Park does better. I really like Pedro's headset press, it looks like a sculpture (I settled for Nashbar's press which cost less than half as much and I can't imagine works any worse, but it isn't as pretty.) I don't think there is a nicer 32mm threaded headset wrench than that made by Park.

Which color do you like ? Yellow or Blue?

They both make good tools, although in my opinion Park has better customer service. I own a PRS-20 bike stand and the CM-5 chain scrubber, broke the BB holder on the PRS-20 after I dropped it and dropped one of the brush axles from the CM-5 in the sink rinsing it out. Park sent both BB holder and axle free of charge.
As for the Pedro's tools, I had one of their chain tools, but bent the pin over time. Not their fault, but mine. I've emailed them about a pin, but never heard back. Although that chain tool sure did last a long time.
Maybe my email got lost somewhere?

Anyway, they both make good tools so I think it's a matter of color.

My LBS said if my Pedros tool ever breaks, just take it back with receipt and they will replace it no questions asked.

my bike shop mostly has park tools and they seem to work out really well.

I've had excellent service with all of the many Park tools I've owned.

I have two Pedros tools, a folding hex wrench set that has been satisfactory and a pedal wrench that had a poorly cut and slightly too tight 15 mm open end that required some Dremel work to correct.

What makes Pedros more environmentally friendly?

Their advertising department.

Well, they have under the seat bags made partly of recycled bike inner tubes, and their lube is natural, and their cleaners are biodegradable.

Pedro's isn't environmentally friendly, at least, they are not any more environmentally friendly than Park is.

I like Pedro's spoke wrenches better. I think they are a better design than Park.

But they make me hungry for pretzels...

Do you tighten the spokes outside or inside the rim with spoke wrenches? Why would you need to tighten spokes? I have 2 spoke wrenches and I don't know what they are for.

You tighten (or loosen) spokes by turning the nipples from the outside of the rim using the square flats on the nipples. You only tighten or loosen spokes to true a wheel or to provide the proper spoke tension to an inadequately constructed wheel.

I tend to buy Park tools because I am more familiar with them, like the looks better, and generally cheaper.