I have both. The X-11 has a little better airflow and more venting but is quite a bit noisier. It also has a fully removable liner unlike the RF-1000 which only has removable cheek pads. I actually prefer the RF-1000 because it is quieter,not much less airflow and it seems to fit my head a little better. Oh and it is cheaper....
i am new to the entire scene and just bought my first helmet, RF-1000 picotte tc-6 (orange and white) and i tried on both arai and shoei helmets. the rf-1000 fit like a gem where the arai was too big and couldnt get a good fit and the x-11 had some killer pressure points on the top sides of my head where it felt like plastic was digging in. those are my experiences with the two helmets granted i am completely new to this but its all about fit try them on. i wear a 7 3/8 new era 59-50 fitted with medium length hair since this does effect fit
The TZ-R is the entry-level Shoei. It's a good helmet, perfectly adequate, but it's a bit heavier and doesn't have as much airflow through it as the others.
One thing to remember is that each helmet will fit differently. Even different helmets from one maker have different fitments. Arai has at least 3 head shapes, so if one model doesn't fit quite right, you should try on the other models before deciding Arais don't fit. Shoei is the same way.