Although you may have already got hands on the latest version of Symbian series like S60 v5. There are many reasons why you should keep a Good Ol’ Nokia Java 40 Series phone.
Here Are the Top Reasons I Feel Why One Has to Have a Nokia Series 40 Phone.
Yeah Nokia Series 40 phones are Malware and virus resistant. There is no known Security Threat for Nokia series 40 except the Blue Bug which is a Bluetooth Vulnerability.
This can be used very effectively when checking suspicious E-Mails etc. If you want to check an unknown attachment you can use the S40 phone to do so because it does not get affected by Malicious Softwares.
I think Nokia series 40 Phones are faster to respond on human interactions like when you click on the Menu Button it takes a while in Nokia series 60 phones but is quick in 40 Series. Although this is not a major factor because responsiveness depends on many more factors and can be tweaked.
Since Nokia Series 60 Phones are feature packed they drain a lot of power although this can also be tweaked by turning off unnecessary services like WiFi and Bluetooth. Series 40 phones are found to have more battery strength when compared.
S40 series has the option to save Recently used and Favorite contacts in the messaging menu. But as far as I know S60 lacks these features.
Recommended Reading: Hack Nokia S60v5 to Install Unsigned Applications.