I'm using this phone for the last 18 months; and this is a great phone; I have a work B'Berry so this one is so light I can forget about it.
PROS
Dirt Cheap.
Tank like built, you can virtually do anything and the phone still works.
Extremely low radiation levels; I used to get headache with similiar (or even 10 times pricier models from other major mfgrs).. with this baby I can talk for hours.
Great battery life; I charge it every 4-5 days.
USB Charging capability (don't think any other phone in this price bracket has it).
Good & Legible monochrome display ( I hate cheap color displays).
CONS
Keys need to be pressed hard; not good if you have to type a long SMS.
I hate all of the standard ring tones it has; but what's vibrator for.
I had the same issue with the locking...Looks like you can turn the auto lock off under settings--> phone settings --> Keypad auto lock.
You can change the amount of time before it locks or just turn off the auto lock.
this is the best phone. ive used it for 2 years (just broke today). dropped from a great height (min 6-14metres) tons of times not a prblem practically water proof ( once i got mango sap and dirt on it just washed it under running water with a lot of dishwashing soap was fine). i got a hole/dent in the screen and it brolke after it gat water in that( i dropped it in a public pool). the best phone ive ever had
Kedar
Picked up one in Australia which was about the same cost as renting in Sydney with a short contract from Vodafone. Found it a little awkward at first since I use an LG in the States. Most annoying feature was the locking keypad (but I didn't inadevertently call anyone either). Decent sound and speakerphone feature was usable when I had to use my laptop. Charged relatively quickly - never used it so long that I can address battery life. I'd buy another one. It's light enough that I forgot it was in my pants pocket.