Personally, I don't think a 56mm objective scope does anything for you that a 42mm or 50mm objective scope of the same optical quality will do unless you are using magnification past 7X or 8X. I own and have used both illuminated and non illuminated scopes of all objective sizes from 24mm to 56mm and all quality levels from bargain basement scopes to the finest scopes humans can build. There are a few things I am absolutely convinced of where good illuminated scopes for low light are concerned:
1. Get quality optics. Good optics and the right coatings are at least as important to low light performance, often more so, than how large the objective bell is.
2. With few exceptions, the truly good, useful illuminated scopes are usually expensive.
3. Illumination on an inexpensive scope is usually a useless gimmick.
4. Too much illumination is worse than no illumination at all because it causes your iris to close, impairing your vision at night, and it flares out the target in the scope image.
5. Few companies actually know how to do illuminated reticles right.
Bushnell and Burris are examples of companies who do a reasonably good job of combining lit reticles in reasonably priced scopes.
The Trijicon Accupoints are very good illuminated scopes with a very innovative battery-free illumination system, above average optics, and good light transmission.
Zeiss, Swarovski, and Schmidt & Bender and several other premium brands offer well designed illumination systems and great optics to go with it, but they are all well above your price limit for new scopes.
To me, the best bang for your buck in a lit reticle scope is with the Trijicon Accupoint. It won't quite deliver the low light optical performance of the uber premium scopes, but it's pretty darn good and its illumination system takes a backseat to nothing!
While on the topic, even though it is convenient to have a battery-free illumination system, I think way too much is made of this selling point personally. With battery powered illumination systems, if the battery dies, the worst thing that can happen is you have a conventional scope that is still just as usable as any other non-illuminated scope. Buy another inexpensive battery and you're back in business. You can always carry a spare battery, and many scopes even have a compartment for a spare inside the windage cap. The wafer style watch batteries that are used provide a reasonably long life. These types of batteries are not prone to leakage, unlike typical cylindrical alkaline batteries. Battery powered illumination systems are not electronically complex, so they are very reliable. Finally, the presence of the illumination controls does not impair the waterproofness of the scope (on a good scope).
The main advantages I see to the Trijicon system are threefold. Once you set the intensity you prefer with the fiber optics cover, reticle brightness is self regulating by the amount of ambient light, so as light gets dimmer, so does reticle illumination, which is exactly what you want. The Trijicon system doesn't have any external protruding switches/knobs to operate the illumination to snag on stuff. Finally, it's always "on," so you don't have to think about it.
Edited by RifleDude - December/31/2009 at 13:28