I recently purchased a Travelsim in St.Petersburg at a local dealer with 10 Euros on the balance (995 rubles, which is 28.68 Euros or 36.93 USD now), so I've already made some tests. The card has MTS Russia network in the preferred networks list. Here, we have four GSM networks: MegaFon, MTS, BeeLine and Tele2. Travelsim gets registered in three of them except of Tele2. However, it actually works only with MTS network (that's why it's in the preferred list, I guess). Although it's registered on MegaFon or BeeLine networks, it's impossible to make an outgoing call or to receive a call (caller gets something like called number error as a voice message or as a phone network response). However, it has no problems with MTS Russia network, I mean both outgoing and incoming calls and SMS (surely, to the separate SMS number) are working. CIDs are correct whatever I call and wherever I receive a call from. I tried some Russian operators to call this Travelsim number (St.Petersburg landline monopolist, MegaFon, some calling card providers), and all of them did work, showing proper CIDs on the Travelsim phone etc. Incoming calls on Travelsim here are free in fact, I've just checked this.
So, I guess a visitor to Russia will not have any problem with Travelsim while the preferred networks list properly works in his or her phone, eventually. It's just necessary to keep in mind than Travelsim coverage in Russia (or at least in St.Petersburg) is equal to MTS Russia coverage. By the way, I'll probably test this SIM in Finland on the next weekend, so I'll tell you my impressions on using it there.