Yes... I'd go for a straight second-hand bootlid rather than a repair, if the repair is any more complicated than just popping out a dented area.
Your bootlid has the advantage of being fairly new, so *if* they can fix it like the dent places do, by easing rods behind the dent to pop it out, then it'll be okay to go that route.
If they can only knock out "most" of the dent and then resort to filler to smooth it off, then I'd go for a replacement bootlid, since a filler'd finish is never entirely perfect, you can get pin-holes forming later and the paint/clear coat will age differently to the other metal panels. The bootlid is a big panel, facing right into the sunshine, so it'll heat up/cool down a lot and you'll be able to see anything in the surface that's not 100% perfect.
Meanwhile... painting a "good" hatch lid from a different car and getting a paint match is about as simple a job as any paintshop can hope for. It'll be easy to get it perfectly right. But take it completely apart (glass and all) .. otherwise they'll shortcut it; mask it up under the glass, where water sits.. and the top coat will lift in time as the water will seep under it.
If the panel is too creased up to fix and/or fill then the shop might re-skin it.. but fortunately this is more aggro' than just ordering a brand new hatch (or using a second-hand one but telling you it was a new one...
) so the paint-shop won't tend to go this way.
If you look at the welded seam inside the hatch (where the outer skin is folded over the inner skin) you'll have a rubbery inset bead that's about 5-6mm wide.. That's the pukka factory fnish so you'll know that the inner join is also clean and won't rot. If the seam comes back looking like someone has skimmed filler over it, then it's been separated and the inner joint is likely to have split the white body primer finish and in a few years you'll have old-styley rust bubbles.
The OE join is infinitely better than any repair... and a second-hand hatch won't be any more expensive than the labour for some fella to poke your old one perfectly smooth (but remember they'll tend to get it 90% there and then skim the surface with filler).
Ralf S.