My favorite part of the 40k season is fast approaching. Ard Boyz!!! This for most is the most active and competitive time every year for 40k. If you don't know about Ard Boyz, it is a national event put on by Gw with three rounds and top 3 from each round advances. Essentially it's a 9 round tournament. You can change your list and army between rounds. You have a month between each round.
40k has developed a meta game over the past two years mostly in part with more and more people jumping on the net list band wagons. You have a few options, jump on the band wagon and net list out a mech army or try to meta game for it and play a counter/ a list of your own. While running leaf blower net lists tends to work well over all. I would recommend against it. There is no originality and you become very predictable running net lists.
Making your own list will let you make your own tricks and plans. It is a lot more fun running a list of your own and playing it well then running a net list. You also run into those who design to beat net lists and can just ruin your day. I am on the fence about blood angels or orks but either way it won't be a net list. I have either my hybrid BA list or Kan Wall orks. In order to play the blood angels I will need to actually paint and build a ton of figures that are sitting in boxes.
Net listing isn't a bad thing just remember to take what your see with a grain of salt.