Had a few dishes in the past and currently seeking a replacement so I share your confusion. Hopefully you find my experiences of help.
My first dish was a Fortec Star 1.2m, but this got distorted....part of a tree fell onto it! Actually worked well, but was on the heavy side for a Diseq motor at just over 17kg I think.
Next, I grabbed an 80cm dish from Lidl for 14.99GBP, this is real budget but does the job...ok for main satellites, but not a good long term investment. I do miss getting channels from the weaker satellites I could get with my previous dish, especially some from 7W.
In my case I am struggling to balance my budget against what I would really like, but here are some suggestions I think you should consider;
Steel dishes are heavy and will go rusty - although cheapest option.
Aluminium and glass fibre will last longer and are light on your motor, but more expensive.
Bigger is better, I would suggest a minimum of 1m (within England planning rules I think).
I cant comment on motors other than my STAAB has performed faultlessly since new, it does have a little backlash, but suspect its typical.
As for LNB's, I splashed out on an Invacom 0.3dB when I got my first dish, but this failed after a couple of years....I heard all LNBs degrade over time, my current 3.49GBP LNB from Lidl is working fine today.
Actually, searching and making up your mind is half the fun, if you select wisely it will be a long time before you need to look again.