Get the 300/400t. Since you've never had the 60csx, you won't know about any of the features which you don't have on the 300/400t. In addition, the 300/400t will probably get better with time as new firmware versions come out. You can't beat it for paperless caching, which is important for this sport. Although I must say Garmin sometimes reminds me of Microsoft with their beta release of products.