c10, I haven't tried Prestige Tour 660, but I agree with Radical, the 102sq. in. is little bit clumsy, so I dislike oversize, but may be suitable for baseliner. I own Prestige Tour 600, PC600, IP600 and LM600, for LM, I just play twice, so I can't give any suggestion, but my opinion P. tour 600 is the best(except Prestige Pro, I really want to try it!). PT may be less feel than PC600, but it's very comfort(with suspension grip) and a little bit powerful. The paintjob and finishing of PT & PC also better than i & LM( the LM QC is quite poor).
At last, on collector's view, I think 600cm2 is more traditional and original for Prestige lineage, the MP, I attribute that to another lineage, NOT Prestige.