I'm a big fan of foregrips and the tri-rail allows for the addition of multiple attachments. It's very lightweight and looks great on the 590. Pretty inexpensive too.
^ It's not bad at all. By putting forward pressure on the VFG I my arm acts as a shock absorber. I don't shoot much for accuracy since I'm not about to get my cheek anywhere near the back of the receiver. It's a lot of fun to shoot though. I'm looking to replace the pistol grip with the new Blackhawk! Spec Ops stock as soon as I can find one. The new ones have the adjustable pistol grip. Then I'll load up some slugs and try some shot placement.