ARC LS-5MKIII or ARC LS-25MKII

Hi,
I am looking for a second hand preamp to my SONY SCD-555ES player(moded European model with balanced outputs), ARC CL-120 amps(balanced), Proac One Sc speakers set up.

I have two offers: ARC LS5 MKIII and LS25MKII for roughly the same price.

Would need the help of those who had the chance to compare these preamps or owned them.

Any comment would be welcomed!

Thanks,
Csaba