I have tried fpdf and a few other libraries for a big job i have done a couple of years back. You might want to look at dompdf, the library takes html and converts it into pdf flawlessly (after a couple of tries to get it right, but still) - only thing is, read the docs - images (like your barcode there) must be linked with server path, i.e. /path/to/image/image.jpg
agree, it's faster but way less failprove to my experience. And the size of the PDF is most of the time relevantly bigger.
generating html and convert it to a pdf is a last-resort workaround.
snapping a quick html for your desired layout is always easier, faster, and more convenient than 1000 lines of $this->SetXXXColor(); and $this->Cell(); and similar
the size (file size) depends on more than one factor. plus, you got a bit of extra flexibility with html converted pdf's. That's what i used and it still works today, 5 years from when i implemented it...