Well technically BL is more value for money, it is cheaper on a psf basis after all. If you are in this for investment, I would say this is not a good idea because you do have to wait 5 years to build and another 5 to sell, and a lot of things can happen in that time, but the 3rm flats are a much better deal in that respect than the 4rm flats if you check the resale prices now.
To me there doesn't seem to be that much difference between standard and premium, especially since now the floors and doors for premium are now also optional. The main thing really seems like the windows. Either full height windows in the living room at MT with not much of a view, or 3/4 height windows in the living room at BL with a view. The bedroom windows are 3/4 height in MT compared with 1/2 height in BL.
If you haven't done so already, just go down to the plots, walk around and pick a spot you don't mind staying forever. It takes maybe 2 minutes longer to walk to BL, but the walk is more straightforward. The fastest way to MT involves cutting through carparks. Also the sheltered walkway to MT is one big round while to BL is quite straightforward. The main drawback of MT is the canal, while the main drawback of BL is the road. If they concern you, both can be mitigated within the particular estate. Ie. in MT you can pick a stack away from the canal or in BL you can pick a stack away from the road.