Hi Sal. You asked comments about Viking Valkyrie bike, but you didn't mention the price. This is all important! If price doesn't matter, there are surely hundreds of nicer bikes for the purpose you stated. Probably price is important. So why the restraint of mentioning an affordable price range or a qualitative indication, like: budget, standard, high-end. All commerical goods have a value-for-money aspect.
It looks very much like this : http://www.discovercycling.com/bikes/Hardtail-Mountain-Bikes/Viking-Valkyrie-Ladies-26-Hardtail-Mountain-Bike.html
. If so, it is a super-budget bike. Nothing wrong with that, as long as you don't expect the quality or features of a standard bike.
Just some general indications that may help you decide:
1. If I google 'Viking Valkyrie' the first page is dominated by 'lady MTB'. Are you a lady (sorry, I am dutch and don't recognize instantly the gender of given names). It so, the bike has at least some frame size features that serve you well, if you have the 'average' female' characteristics.
2. Generally, the geometry looks more for relaxed touring than sporting MTB rides. Is this what you want?
3. The Suntour front shox is more suited for touring on bad pavement or off-road on gravel roads and smooth double tracks than for MTB trails. It certainly isn't bad or soon-to-fail. Rather it is more robust than finesse: more Lada than BMW!
4. From the pictures it looks like the bike has eyelets for screwing a rear rack to the seat stay. I am not sure about eyelets for screwing the rack near the rear axis. This is important if you want to carry gear for a multi-day ride.
5. The 36-spoke wheels are probably robust for carrying big loads and won't fail easily. I didn't see the bike's weight, but it won't be lightweight. That fits in the profile of a touring bike rather than a sporting bike.
6. The 21-speed (3x7) transmission is more in the starter range than in the standard range (3x9 or 3x10).
5. I favor disc brakes over rim brakes, so I won't criticise this, except that it is a miracle that they feature in a super-budget priced bike.
I won't say that this bike doesn't last, but it probably doesn't satisfy in the long term. In my opinion, as long as you are not clear about the long-term purpose of the bike (say: one-day rides vs multi-day rides ; easy trails vs demanding trails ; budget, standard or high-end) this is a nice and inexpensive way to learn about your preferences. It will probably satisfy you for 1-2 years. After that you will be much better informed about what to look for.