I like the cage...remember though,budgies are fast flyers,so they'll definitely need out of cage time no matter how big the cage (unless you go overboard & make an indoor aviary out of a room or something I'm guessing,but i'd still let them out either way

) About bar spacing,i'm really not that sure...I've heard people say before it shouldn't be more than 1/2 an inch.& I can't remember what size mine was now since it's all taken apart... >.<
The cage is quite nice though I must say! Also when it comes to seed guards (things on the bottom there) make sure it goes all the way down,birds can also escape from there...
Another option though,is if you got a spare room,you can turn that into your aviary XD
I have a cockatiel,whom never did like cages.Loves to sleep in it,but close the door during the day& she gives you the look of death...