Arduino or PIC microcontroller?
Really the question should be Arduino vs Launchpad (or another PIC development board) or AVR versus PIC. Arduino is simply a development board that includes an Atmel AVR processor and the necessary hardware to use it.

There there tons of custom shields available for the Arduino, including a wifi shield. Open-source wrapper libraries are already available for most of these shields, which will shield you from a lot of low-level bit twiddling. On the development side, you can simply use a GCC cross-compiler (avr-gcc) and the related cross-toolchain. This is not true for PICs, which are not supported by GCC.

If you don't mind the cost of an Arduino and the necessary shield(s), Arduino is likely the path of least resistance. The available libraries and support far trump any technical advantages of a PIC devboard unless you already have a lot of experience with microcontrollers.