It is already discussed here:
Sadly, I was right about the Alchemy Lab not being useable for transmuting things
And not like as we hope:
PROPOSAL - New Building: Alchemy Lab
So, IMO, I do not want build and research AL, I just focus to SH lvl 25, an waiting Hero Academy and hope it is good and worth.
EDIT:
But, if you dicide to use AL, It would be great sharing your experience here, because everyone has variety playstyle and also mode F2P, VC2P, C2P, P2W. Thanks.