Go WO or go Commissioned?

The best thing for you to do in asiting with your decision process is to seek out a warrant III who made the transition from enlisted (someone with experience) and ask about all those things of which you are uncertain, do the same with an officer who has at least held Company command and was prior enlisted. Lastly seek out a great 1SG and CSM and ask them why they never made the transition. If you do this you should have all of the info you need in order to make an informed decision. Thank you for your service.

Go warrant as a 120A? OK, I went Commissioned and don't regret it, but I was never offered the chance to go Warrant either. The Disadvantage on the Officer side is that it's either up or out and it starts getting very competitive at O-4. In addition, after you get your command time, everything will be staff time until after you hit O-5, which can sometimes be a bit of a drag.
OTOH, my time as Engineer Co Commander was the best job I had in the Army.
As a Warrant, you get to do your job, the pay scale is very near that of a commissioned officer (actually better in certain cases since you don't max out as quick) and you have enough authority to not have to deal with most of the more mundane tasks that need done in the Army.
Engineer BOLC isn't easy academically and I am told that 120A is not a cake walk either.

Something to consider: Professional Military Education. Commissioned officers get the opportunity to take robust PME courses throughout their career and even work on their Masters degree later on. Why does that matter? Once they get out of the service, they are very competitive in the defense contracting/GS industry. Most defense contracting companies will write into their job requirements “must be MEL-4 qualified or equivalent” or “JPME II qualified” on certain job positions (ie: planner positions or strategic organizations). What are those companies looking for? Retired field grade commissioned officers. Just something to think about.