We would've used an immigration attorney, except we couldn't find a single one who was a) competent and b) not trying to rip us off.
We're doing the application through some weird undocumented loophole because the USCIS is so swamped with applications the "proper" way involves starting a business here (with all the expense of doing so) then going back to the UK and leaving the business dormant for 9 months until you reach the top of the pile. This loophole method lets us stay in the US, takes 15 days, but we won't be able to leave the country for at least a year.
If it comes back accepted we can stay here. If not, we're out within a week and will have lost everything.