I run one on every centerfire can I have. Mirage is drastically increased by a hot suppressor and IMO a cover is mandatory for shooting groups or long strings with a hot suppressor.
Covers offer other advantages like camouflage, sound dampening if you bump something, protection from scratches and keeps you from getting burned by grabbing a hot can.
I've seen most brands and own 4 different brands, TAB Gear, Armageddon Gear, Rausch Precision, and Cole-Tac. IMO the Cole-Tac is the best one on the market.