i'm regularly selling casascius coins for paypal. if you're just looking to collect/save bitcoin this makes sense. if you're looking for btc to spend/use the markup might be a bit excessive for you
https://bitcointalk.org/index.php?topic=131828.0current markup is 17% of a btc plus 5.3 shipping (assuming US - international shipments that include tracking get expensive)
i rebuy bitcoin as these sell and money is in a constant cycle from my paypal to bank to other bank to rebuying btc so sales happen when i have the dollars to rebuy btc (at the moment slightly over 1000 is available)