I have a six rack and it has served me good so far. I have had it since last spring or abouts, so my cooking experience is limited. If I had to guess I would say I have done about 7 cooks in it.
I would read recipes on the site with time guidelines and I can never meet them. It always takes me longer......but that does not bother me. If I am cooking a seven hour recipe I have to allocate a chunk of time for the cook anyway so what is a couple of more hours.......less work around the house is what it is to me. Cause we all know how back breaking smoking food can be.

I have done ribs, pork butts, and made 24 pounds of bacon in one cook. All turned out top notch, not just my opinion as I have feed plenty and they keep asking for more.
One day in the fall I checked my digital temp. readout on the SG against my Maverick and the readings were bang on (for about an hour ride)....till I put meat in the smoker. Then there was fluctuations between the two. I use my Maverick thermometer read outs after inserting meat into the cabinet.
I am happy with my six rack and I am also happy that I made the decision to get the extra two racks. When you say "it went wrong totally" if you elaborate maybe we can help.
JJ