This website has comparisons of many SRC algorithms and is a great resource for seeing which ones are usable and which are not: http://src.infinitewave.ca

I see that Sound Forge has elements of iZotope RX, Ozone, and Nectar built into it, which is awesome. I've recently started using these myself as Pro Tools plugins, and they really do sound great. You can get some very good results from them if you know what you're doing, so if this is what's being used for laserdisc audio preservations, so much the better.