If you can invest in something that will give you a better return after you've liquidated your SOL holding and allowed for the tax on your profit then, yes. The question is "are you sure you'll get a better return?".You must have had a profit margin in mind when the purchase was made, so maybe stick to your original plan. Personally they are my biggest long term holding and will continue to hold but liquidated all my CFDs in the 490's.
Have any of you read The Prize by Daniel Yergin? Essentially it is a very comprehensive and complete history of oil, well worth the read. From it you can see that oil throughout history goes through phases where the price climbs and climbs and the increased price then makes new means of extraction financially viable. These new methods of extraction bring huge new volumes of oil to the market resulting in a price collapse. I essentially think this is happening at the moment with Shale gas. News out today is that the USA is now once again the biggest producer of oil in the world thanks to Shale and I don't see the shale production stopping any time soon. To summarise, I can't see the price collapsing in the next year or so, but in 5 to 10 years I think we are more likely to see $50 oil then $200 oil. Still think its a great investment for the medium term though