Set the 942 to daytime only mode and see how it works for you with the 60W light. That will give you and idea how the 930 might work, because that one has daytime mode only. I have both, and I think the 930s aren't as good in low light. I'm not sure if this is only because they don't have a night mode, or if there are other reasons. Performance varies if you depend on lights being on. It all depends on how bright the light is, and where the camera, light, and object being illuminated are. If your subject is being lit from behind, or even the side, or too far from the light, you may not like the result.
I think the 942 has better firmware with better options (the 930 has less memory to hold the firmware, so it has to be smaller with fewer features). You get finer control over the motion detection area. The 930 motion detection definition has fewer, larger blocks for selecting what areas to monitor. The 930 doesn't have the PIR motion detection option that the 942 has. Also, the 930 doesn't have as good a control of how many emails you get. Setting to email on motion causes it to send out pictures as fast as it can (more than 1 per second for me) until motion stops. I didn't like this flood of email, so I chose the only other option that made sense: one email with a series of 6 pictures at 1-second intervals. At least this way I don't get more than 1 email every 6 seconds (and most things I'm monitoring are out of view by the end of 6 seconds, so I usually get 1 email per event). The 930 also can't add a timestamp to the image, if you care about that (but it does include a timestamp in the email, and in the filenames of the pictures). For viewing live video, the 2 cameras work equally well.
One other unexpected difference is the 930 has a shorter power cord.