My experience with UPakWeShip was great, with no extra costs.
They quoted me a set price for a volume of boxes taking up 100 cubic feet. They didn't seem to have a weight limit, so I pakced what I wanted as long as it stayed within what I measured at home to be the 100 cubic feet.
You do all your own packing with UPak (hence the name: "You Pack; We Ship").
As for paperwork, customs, tax duties and getting a customs and duties man ( I think that's what they are called) -- other companies told me I'd have to find and hire my own for a whole separate fee paid to that person/operation.
But UPakWeShip offer all of those services; they took care of all the customs and duties on the arrival of your shipment to port. I think the one and only thing more to pay was a £34 port fee I think...but that was told to me up front before I'd even shipped, so it was not an unexpected extra.
I went with Upak because weight didnt seem to be limited, the cubic volume was more than enough for me, and because they offered all paperwork done for me at arrival port, while other companies said that was a separate thing I'd have to arrange, which sounded like one more headache to me.
The only "paperwork" UPak do require is that you fill out their own forms that they e-mail to you, with simply details of the UK delivery location, a contract, and also, they ask that you send them a list of the type of contents of each box. I went overboard with details of every item -- not sure they needed that, but everything when through smoothly at customs as it seemed like they didn't even open my boxes to check. (Customs man must have looked at my tedious lists ["1 book: "Harry Potter and the....."] and thought "Yeah yeah okay....")

For pick up and delivery, they can do door-to-door, picking it all up from your home and delivering it to your new home, without you having to take it anywhere or go get it. Or you can do half -- in my case, I took all my boxes to the local designated dropoff warehouse, thus saving some money of UPak's total quote for full door to door. Then I had them just deliver straight to my door in the UK. Or you can pick it up from port if you want to.
I felt they offered a great service. I had called several local and not so local companies who faffed around talking about having to pay separate fees for what happens at the UK port, and they also charged much more. UPak was so straight-forward and simple in what they offered that it was a breath of fresh air so I went for it, and found them great to work with the rest of the way. Very happy with my experience of them.