Biz visas are better because they allow you the most flexibility when it comes to traveling. They can be ordered as 'multi-entry', allowing you to exit and re-enter the country as many times as you wish during the valid period of the visa without having to buy a new visa every time.
Example: Say you want to meet your gal in Moscow, then jet off for a lovely vacation in Aruba and after that escort her back home. With a biz visa you could enter Russia to pick her up, exit and then after the vacation re-enter Russia on the same visa at no additional cost (except registration fees).
Yes they cost a bit more at the outset but they are worth it especially if you plan on more than one trip per year.
On a biz visa you can't stay in the country for more than 90 consecutive days at a time but that really isn't an issue unless you plan on living in Russia full time.
I'm not sure what the latest registration rules are as they change frequently but I believe that each time you enter the country you are supposed to re-register the visa and also you need to 'de-register' the visa when you leave. I have never bothered to 'de-register' and it hasn't caused any issues .
