anyone have any input on installing one themself with good luck.  are there any downsides to using one

Can't help with the install portion of your post.  My Ranger came with one installed.  Hamby's in my case.  As for any negatives, I cannot think of any reason I wouldn't want it on there.

You can easily do it, I did.  a couple of hints...1. start it out right under bow eye and dont cut any off, it should go to where keel flattens...2. buy same color as boat bottom.

Read, I say read !   the instructions.

i wouldnt have a boat without one ...also look around at different colors   some colors look real good  being different than the hull color

My boat came with a Hamby's as well.  I wouldn't own a boat with out one.

I have installed 3, on my last 3 boats (Keelshields).  And used a different color than the bottom.  Just picked out one of the trim colors on the boat and got that color, looks good.  Bottom line is take your time, and it has to be warm weather or it won't be flexible.  Once you stick it on your boat it's stuck, be careful and it's no problem.

from what my dealer showed me i would only go with Hambys.  Hamby's is a piece of fiberglass that is in someway attached to your keel.  I dont know if it is a "do it yourselfer" item or not.  I will have one on my new rig very soon!!