My VT100 MKII is coupled with the LS25 MKI (NOS 6H23 6922 tubes). In my system, I prefer the tonal balance and the overall performance of the LS25 MKI to the LS5 MKII. The LS5 is also a very good preamp.
As a reference you can view my system at the following site:
http://forum.audiogon.com/cgi-bin/fr.pl?vdone&1126482564&view