they're 100mm rear travel, right?
98mm, pretty plush so will bob if you dont know how to ride an FS bike properly.
geometry, sizing,
Pretty standard, Seat-tubes are long for their size (eg. Medium is 19" ST but length wise its the same as any other brand) but obviously standover is fine due to the dsign.
type of riding, etc? Is it a racey bike?
Yes it can be, stick light stuff on it and it will fly uphill and still be capable of going down. Build it like a trail bike and it will make mince meat of pretty much anything you take it down.
would 120mm bolt through forks suit it fine?
If you get a later maodel (07 on?) they were built a bit stiffer than the early ones. I have an 05 with the alu back end and a 08/09 i tried was stiffer even tho it had a crabon back end. Dont expect to make it into a 'hucker' tho as you cant get anything bigger than a 2.1" on the back (at least on my 05). But if you want steering precision then yes it would be a idea.