MTB Why are 29ers considered better then the legacy 26'' or 27'' tires? this is my first time here however I am a long time stackexchange user.
I am planning to get a new MTB. Haven't ride for a long time 10y ago, as a kid I was always riding a MTB (I had an old low budget MTB and I don't want to ride it anymore).

I was considering to get this bike:
http://www.cube.eu/en/bikes/mtb-hardtail/analog/analog-29-black-grey/

As you can see it's a 29er. Basicly I wanted to get 27.5 or 26 however at every store at my country they are telling me that 29ers are the best.
Can anyone of you more experienced users tell me why should I prefer 29'' tires?

Also what can you tell me about the bike? I don't have much experience since my last ride on a mtb was about 10y ago.

This bike is 720eu at my country and I am getting it at a 20% (570eu) discount and this is as high as possible for my budget.
So am i getting something worthy for the price?
Simple answer 29er wheels roll better that 26" wheels this means better rollover and higher speeds. These are good things for mountain bikes. The trade off is, because they're a larger wheel they require a larger frame. This is especially true for suspension. Usually 29er don't have the same range of suspension as 26" wheels. The larger wheels compensate for some of this on rough ground, but that doesn't help if you're taking large drops.

So really it comes down to what kind of riding you want to do. If you want light trail use and cross-country riding the 29er is ideal. Since you're considering a hardtail I think this is you.