I've never RMA'd through Monarch, but from what I've read about them they're not too bad...I believe the warranty is through AMD, but I'm not 100% on that...other forum members would probably know better than me
That said...$15 is a small price to pay for a little peace of mind, whether it's warrantied through Monarch or AMD...
When Sparco crapped on us I worked something out with a friend of mine, so now I'm aiming for Monarch's 4000+ OEM hopefully shipping this Friday...and I paid the extra $15 for the warranty