I started using BeerSmith late last year, soon after I started brewing.
I've made the transition to v2.0 pretty easily. Sure, it took a little getting used to, but that's to be expected whenever a major overhaul is performed on an application.
There are enough enhancements in BeerSmith 2.0 to make it well worth moving to. For one thing, when you change your mash temp, it adjusts the FG estimate. This was not present in the previous release. It does mean you need to record your actual mash temps now, and/or make sure you hit what you're calling for. But, it does mean you'll be able to have a better idea of what to expect in the final product.
There are plenty of other changes that make it worth getting, IMO... I tend to work through application changes instead of letting them paralyze me with fear. Especially when the small changes (different skin, things moved around, other interface changes) prevent me from taking advantage of greater enhancements.
Personally, I just picked up a tablet that runs Windows 7 so that I can run BeerSmith (v2.0) on that during brew days. Maybe it's because I'm in the IT field that I don't have a fear of technology (pretty much anything out, or coming out)...
You can try BeerSmith (v2.0) for free for 21 days before you need to decide if you want to purchase it or not. It took me far less than that to get used to the first version. Took me less than one evening of playing around to get comfortable with v2.0... YMMV