I like Seafoam Deep Creep, can't say its the best I've not used everything but I am satisfied with it's performance. When given any chance to do so I will spray parts, and give them as long to sit as possible.
When working on my own vehicles and knowing I'll need to work on it within the week I spray, and give it time to work. Obviously not always an option however it works well for my, and my personal vehicles.
The first time I uses Deep Creep was on a strut I had to replace, sprayed the mounting hardware down, anything I would need to remove. Not drowning the bolts in it just a quick spray on both ends. I remember removing the lower control arm bushing bolt, probably 4-5 inches long, in that time the spray made it the full length of the bolt with the bushing blocking 80%+ from direct contact.
Its worked well for me, I also like some of the non petroleum based penetrating oils as well (yes not technically an oil) like "Super Slick Stuff". Sell it locally at Lowes pretty affordable.