Personally, I love my Creed(s) - preferring them to the Ego that I had, and have had no major problems with them. Sadly Creeds have got a bit of a bad reputation for leaks.
From what people have said, there is quite a bit if inconsistency so one marker works well, while the next would be a dog and have endless problems.
Creeds are currently very cheap second hand (absurdly cheap in some cases), but the company was recently bought out, manufacuting moved to the US, and the Creed discontinued, so spares may get hard to get hold of in the future.
If you can get a good one, they are well worth it. Finding a good one may be a challenge though...