e61i is much better.
-Reception is amazing, never had a dropped call even in areas where My S620 and DASH dropped calls.
-battery life is amazing, even with wifi usage, text messaging, calls and watching videos the battery lasts.
-screen quality is amazing compared the S620
-stability, my E61i hasn't froze and turned off or any of the bugs that windows based phones has
-ease of use, it's a lot more simple to use than the S20
-faster wifi, the wifi abilities in terms of range and speed the wifi on the E61i is much better
-easier to personalise, the E61i doesn't require hacking or changing codes as far as I know
-E61i is not that expensive compared to other QWERTY phones.