[Wdll]

You don't use trucks to ferry troops to the frontlines, it's suicide. Some basic rifle fire can destroy the truck and some or all of the troops inside it.
The best thing about APC/IFV is their armor, protecting the troops inside and outside on the same hex, from small arms fire and light mortars etc. Try to use a truck for cover...only in movies.
Then the extra gun(s) are just a blessing, suppressing fire or just killing things. The basic M113 can do its job, but then it depends on what you are looking for. The cost increases for IFVs and you get what you are paying for, be it extra armor, or weapons or TI. But you must never forget that even them are not built to fight your battle and they are definitely not tanks.

I use trucks some times, but in most cases they are just too fragile and/or too slow.