are you looking to use your digital as a "polaroid" in order to check lighting setup, or to check exposure?
1. I've used a digital at times to check *rough* composition,(crossed shadows, etc).
2. I'd recommend NEVER use it for checking exposure. Use a handheld meter. This is a recommendation, many of the pros that I've come across, or assisted for, still use a handheld meter to check exposure before shooting it on digital. Then they shoot tethered to the computer, or shoot to a card, then look at the files on the comp. They've all recommended NOT trusting the LCD for exposure latitude(many of them also don't use the histograms much to get exposure correct, rather relying on lighting ratios), just like shooting film.
besides, in the film days(i still shoot film mostly btw), YOU would need to find the actual SPEED of your film that gave you the results you liked. Say, shooting a 160 speed color negative film, but you like what rating it at 100 gave you, a 2/3 stop over-exposure, this generally would make colors a little brighter and give some "pop" to the image, also lowering contrast slightly.
shooting chromes(slides) is a different ball-game. your exposure latitude is smaller(considerably), but the lighting ratios are the EXACT same. Personally, I shoot color negs like I would slides, they perform best in the 2-3 stop range of highlight-->shadow density. Just like digital.
besides, if you get the image right in the film(or digital), BEFORE POST, then it makes your(or your tech's) job SOOOOOO much easier.
shooting chromes(slides) is a great way to learn how to light. you don't have much latitude to work with, so learning lighting ratios is key! But color negatives have 2-4x more range than slide films, and can tolerate underexposure much better than slides. (Still don't recommend underexposing though, unless you like blocked-up shadows)
just my $.02