Well, an illuminated recticle can be very good. But, IMHO, just as important is a scope that can resolve in low light. That usually means at least 50mm.
I have an ATN 3x9x55LU. On a recent baited bear hunt, it really helped. Bears often do not come in to the bait until an hour or so before dark. In many cases the longer you wait, the large the bears that come in. With the resolution that the scope provided, I was able to discern more than I was with my naked eye. I stayed on stand past legal shooting time, just to see what would come in. I finally lost resolution about 50 minutes after sunset. Could still see the illuminated cross hairs though. /ubbthreads/images/graemlins/smile.gif
I am not recommending the ATN, however. I feel that it has some other issues. It is a pain in the neck to zero that scope. It is a matter of ergonomics. The elevation adjustment is deeply recessed, so much that you can not see how many clicks you are moving it. /ubbthreads/images/graemlins/smiliesmack.gif Also, by design the reticles change position as you change zero. This is something that was common years ago, but most makers have gone away from.
It is supposed to have a bullet drop compensator that uses cams. I have never been able to get it work correctly.
On the plus side, I did take a 300lb black bear and a fallow deer with it.
The large glass does add weight.
I also have a BSA 6x24x40 that is illuminated. Though I didn't purchase it because of that, but rather as an inexpensive 22rf scope, besides, Midway had it on sale.
In both cases, the illumination is adjustable. Be aware that the brighter the image, the more you have to turn up the illumination. There is a trade-off point where the reticle can cause the image to loose resolution. I believe this is because of internal reflections.
For some of the top of the line scopes, eg, the Zeiss Diavari 6x24x56 it can become very expensive $1,899, while the Leupolds are in the $1,000 range. I own several Leupolds and can highly recommend them. However, I have never owned an illuminated Leupold.