I can only tell you what I have read, no SLP real-world experience here (sorry).
I have not read of any 'cons'; the fit and finish is excellent and the sound is comparable to the other high quality catted x-pipes. The price is competitive, too. SLP makes their x-pipe so that you can re-use it with long tube headers, if you install them at a later date. IMHO, SLP makes good stuff whether you like the fact that they used to cater to the F-body crowd. (I sure don't mind, more competition and choice is good for us!).