If you spent the time and effort making the Hub never delete it. Don't even unpublish it! I had some Hubs that I thought would never see 2,000 views, but as time goes by they all did! Basically, you want to keep the jackies.hubpages.com/YOURHUBURLYOULOVED forever since date is a factor for seo. Most of the time we make the best keyword URLs we can when we write hubs and others wish they had them. Its best to promote it and make small updates and corrections for at least 6-12 months. If it doesn't meet your personal quota after that time erase all the text and reword it. Sometimes, if the product or subject updated you can re-purpose it.
The only time I suggest deleting a hub is if it no longer exists, isn't fitting your "brand" if your a writer who only writes about cats and your dog hub isnt getting views delete the dog one. Most hubbers are "Jacks of All Trades" writers who have many different subjects so its best not to limit or delete.
Best of luck,