I use Silverfast with my V700, but like a lot of people I tried both Vuescan and Silverfast when I first bought the scanner a couple of years back, found the interface for both to be pretty horrible and just stuck with the Epson software. As people already said, with Epson Scan you get good batch scanning options and the results aren't bad as long as you turn off all of the auto settings and use the histogram/levels/curves settings to avoid clipping any highlights/shadows at the scanning stage.
Anyway, about a year or so later I thought I'd give Silverfast another go - I still found the interface horrible to begin with, but I persevered and rescanned some slides and negs I had previously scanned using Epson Scan. In terms of sharpness and contrast the two are much the same, but Silverfast produces noticeably better colour balance, particularly with colour negatives when using the correct film profiles in negafix. To some extent you can improve the colours of the Epson Scan output in whatever image editor you use for post processing, but particularly for C41 film I can never get such pleasing results as when using the appropriate negafix profile in Silverfast as a starting point.
I normally scan at 3200dpi to a tiff file, open that in Photoshop and then save it again as a tiff file, but with LZW compression, which dramatically reduces the file size. If it's a photo I really care about, especially if it was shot on a tripod, then I'll scan at 6400dpi and then downsample to 3200dpi in Photoshop afterwards. This does give a slight boost in sharpness compared to scanning at 3200 initially - nothing major, but it doesn't cost anything. The resulting files are quite large (approx 60MB), but storage is so cheap these days that assuming you have a sufficiently fast computer to cope with editing files of this size, I don't really think it is much of an issue.
I also use the betterscanning.com 120 holders with the ANR glass inserts. I did some comparisons against the standard holders to see what kind of improvements are available. For my particular V700, I found the sharpest results for both were with the holders set to minimum height, though within reason changes in height didn't have a huge impact. Perhaps because I am scanning relatively flat negs to begin with, I didn't notice a massive difference in sharpness between the two holders, however the betterscanning holder did get rid of a small amount of distortion present in the scans from the Epson holder, by eliminating the small amount of curl still left in the negs.
The betterscanning holder + ANR glass is also faster to work with than the Epson holder - just drop in the film strip, put the glass on and scan. No fiddling to get the piece of film as flat as possible before scanning.