First Bike Kit?
There are a few makers out there: Italeri, Revell, IMAI(now gone), Aoshima Tamiya, Protar, Heller, etc.
Tamiya & Aoshima (IMHO) make the best Models, Protar & Revell (often same kit but Revell costs more) are not that hot.
Italeri is Italeri.
Good Kits for a beginner are some of the cheaper and older Tamiya Kits, go for a plain road-bike like a Katana, CB750F, or similar
Aoshima are a bit more tricky to assemble but still nice Kits.
Imai used to make some rather "not so nice" Harley Kits(I think Tamiya got the licence now), just before their demise thei released a set of 6 custom harleys that were quiet nice as you did the same customisation steps as on the original Bikes.
One big advantage I see of the old IMAI and Aoshima Kits is that you end up with plenty of spare parts for the spares box.
For a beginner I would recommend some of the Heller 1/9 or similar Kits.
Aoshima and Tamiya tend to have often plenty of plated parts, which I strip and repaint.
On all of the Kits you can do quiet a bit of customisation and improvement.