I have been using the Scopecoats for a couple of years now. Scopecoats are simply stretchy sleeves that encompass the rifle scope, protecting it from the elements and particularly from rubbing and scratches. They are made in two weights and althought I bought several heavy ones I would suggest the lighter model as they are much easier to put on and take off. Available from Cabela's, Brownells, other retailers or direct. Cost is moderate and they are very well made. Custom fit models for BIG scopes available.
I particularly like them for storage - my gun safe is too crowded and I hate having scopes rub against each other. With the big scopes available today this is a problem.
Although the tactical scope crowd is hung up on flip-up scope caps, the Scopecoat offers much better protection. I have been able to stretch the lighter Scopecoat over Butler Creeks - total overkill but the scope body is protected.
Positives - excellent protection from abuse, scratches, rubbing, moisture. Will stand up to hard use.
Negatives - what do you do with the Scopecoat after you take it off in the field? I usually stick it into the guncase but in hunting situations it is another thing to store and not lose - usually put it into a pocket or backpack.
I have used the rubber bikini covers also and had a set wear through in only one mountain hunting trip (scabbard wear). Saw another set get cut when the rifle was dropped during the same trip - we threw two sets away as they let moisture in onto the lenses and trapped it there. The rifle with the Scopecoat was fine through some nasty weather and handling.