If you are considering bench shooting, then a light trigger is great (I used 2 ounces). But, it has to be a single stage, as you just can't manage two stages in a light pull trigger. Seems air rifles are almost universally two-stage triggers,which are fine for most applications. Release weight is a matter of preference, but it must be clean. I use my Crown at about 14 ounces release; I'm holding about 6 ounces at the first stage stop, so I need to apply an additional 8 ounces to release the shot. I have found this to be very usable in casual target and hunting scenarios, where you need absolutely safe trigger control. My Steyr and RAW are set at about 6 ounces, divided about equally between stages. This is a great setup (for me) for target shooting, but would not be practical for hunting. Put on gloves and you have a totally unmanageable trigger. Not many air rifles offer really good, two-stage triggers. My Steyr is an example of one that does. It has separate weight adjustments and springs for each stage, so you can set it precisely, up to a maximum of about 8 ounces. A true, two-stage trigger is a wonderful thing. Service rifle shooters have a minimum pull weight of 4 pounds, heavy (it's a service rifle). But, a good match trigger can be set up to offer a 3 pound plus first stage, so the pull to release is very modest. These are shooters who put shots into a dinner plate size target at 600 yards, with iron sights! Try it sometime, the front sight blade covers a car at that distance.
I recently bought a Daystate Red Wolf, a rifle that has an electronic trigger most reviews drool over. I believe, folks who offer such praise have never used a really first class, mechanical trigger. I'm not knocking the RW trigger, it's good, but it's not in the class of a precision mechanical trigger. It's a pressure switch, not a sear-and-lever engagement, and it cannot be as clean and crisp. But, I have to admit, it's.......interesting. And with practice, one can shoot well with it. I have found that at light settings, it is not very controllable. I think a lot of folks are impressed with the very light setting, but there is more to a good trigger.
I digress, a good trigger must offer a crisp, clean release, The weight, and style (single or two-stage) is totally a personal preference.