I think there is an element of luck. They cant test them all in the shop! All my seeds have sprouted and grown fine from them but I had a problem with another supplier.
I bought 2 easy ryder AK47 and they are both growing well. One is tall and light green, the other is short and dark green. The have the same soil, water, nutrients and light (slightly less for shorter one). I know this because I planted them in the same pot! Tut Tut. I didnt think they could be different heights. Different mums I suppose.
I couldnt find a reliable place to germinate my seeds so I had quite a few fail for different reasons. I bought a Garland propogator for £20 and it has paid for itself already. Looking back probably all the seeds were OK. Plus I know to look the next day as it is less variable. Once sprouted it is into a mini pot with a see through lid (to keep things moist) and hey presto.
Reading the forum, people seem to spend a lot of money on seeds but then don't follow up with a good growing enviroment - one small bulb, small pot, bad drainage, too many plants per bulb, etc etc.
If you get the germinating, soil, light and heat right, then you give them a very good chance. If things start to go pear shape then usually you can improve things by flushing or more/less nutrients. If it is already struggling you are going to get a poor harvest at best. At worst failed plants and a waste of your time, bulb life and electricity. All those hours of dreaming really do go up in smoke.
It might sound obvious but the number of photos where the seed is probably more expensive than the set up.......If I am paying £9 per seed its going to be travelling 1st class all the way. You get a better harvest too so even more bang for your buck.