Hi friend dont go for both the nokia's yes 5130 as well as 2700 is dead slow both models are owned my cousin and my friend i used it and verified but honestly speaking 5130 has more application support and flash support but the samsung does not but performance wise and music wise samsung rocks.
what is problem with you bro , is samsung bribing you or someone from nokia kicked in your ass.
i have no idea what virus problem are you talking about . i am not aware of a SINGLE virus that exists for s40 .
5130 is excellent mobile and it handles 8gig card with No problem . if you have slow software then its most probably you are using old firmware . i used 8gig card with 1400+ songs for a week , it performed perfectly normal . this phone can rival any phone in sound quality , including phones that costs 5X more than it , check GSMarena's test.
2700 is also okay , its i bit slower than 5130 but nothing to worry about. but battery life is shorter(2 days) and i personally didn't liked the keypad.
samsung model is also good with marginally better screen . but they have many little bugs in software i hate . java apps on samsung is PITA . i think its better to avoid low end samsungs .