Encryption is not to important in MY opinion, just the packing.
Packing the data makes for a tidier 'project' directory on the client
PC and can be seen as the 'first' layer of encryption, weak but there.

If someone has to 'hack' to open the packing then they know they are are performing "evil".

Heavy excryption is expensive, and still no guarentee to be safe.
A good hacker will still find a way in. Be it a custom-written extractor,
or a ram-scanner.

I prefer to use a simple packer, but have embedded signatures every asset,
so if someone does strip my assets and re-uses them, the signatures are still buried in them
and can be used as proof of piracy at a later time.