The A2 frontsight is your gasblock/frontsight now, if you want a free float you have to switch to a low profile gasblock that fits under the handguard and you lose your front sight post.
Chopping the A2 front sight post is complex and unless you are very comfortable with power tools/have a nice vice and other tools required to disassemble an ar-15 i would not recommend it. Replacing the A2 front sight with a low profile gas block will require the same tools but will require no maching/cutting of the A2 sight. The magpul forend was designed for people who just wanted an easy drop in replacement that allowed for accessory attachment without the need to buy any specialty tools.
So it all depends on how involved with the ar-15 you want to be. if you see yourself doing a ground up built someday, sure buy the tools and get the free float and install it. Personally I like the A2 front sight post and look of the magpul. get yourself a nice magpul forend with a decent optic that lines up with the A2 post i.e. co-witness. Combine that with your BUIS rear and you've got a very nice setup.