On VHS... SP mode is 2 hours, and EP is 6 hours. 2 hours is better quality than EP because sometimes EP tapes will not track good on VCRs.
Recording speed is not a concern for storebought DVDs. It's just if you have a set-top DVD recorder (or recordable DVD player) and you're recording a DVD in 6-hour mode, the quality won't be the best.
I recommend obtaining the Little Rascals DVDs by Cabin Fever that you'll always find on eBay. Of course, it's because they're uncut and on *DVD*, very high quality. Unfornately, only the first 12 volumes have been released on DVD. Volumes 13-21 never came out on DVD.