>>96410979
Honestly that's a good box to get into the game. There's a smaller game format called combat patrol and that box provides two combat patrol boxes and terrain to set you up. You can even grab two to have a full terrain setup for an actual game, as combat patrol is played on a smaller 44x30" board instead of the usual 44x60" one. Combat patrol is 40k lite, missions are simpler, datasheets are nerfed so your units and armies have less abilities to go around with but the overall mechanics are just the same so it can be a good intro.
I would suggest trying it out first before spending money on an another faction. I started at 10th edition about a year ago I can't really compare it to the older editions but the game is easy to understand rule wise, but can become extremely complicated if you wish it to be so. But for casual combat patrols, which I also played a few games myself is easy enough to follow.
>>96410998
A friend collects them, honestly it offers a huge discount and keeps you busy by sending models to you each week but if you want to pick up a certain army it may not be a good deal as you end up with 9 factions and you can't play normal games with any of them. I think it makes sense to subscribe it with a few friends who might be interested in the factions they offer in the subscription, then buy separate kits to complete those factions.