UHMWPE is also super slippery, more so than HDPE, so it can be a lot harder to machine as a result and I imagine that would carry over to RG1000. I've heard tell that this can be useful for avoiding getting grabbed or for getting out of tight corners but I'm doubtful it makes too much difference.

We've used HDPE so I can talk a bit about our experience with it when it comes to working with it (it never went into the arena!). It's a nightmare to cut, or rather it can be, but you can do it with either a jigsaw or a bench saw so long as you have the appropriate blades for the job. You'll need to cut at a low speed to avoid it melting mind, that caught us out even at medium speeds! Get that right and it's easy, but it took us quite a few goes to get it figured. Flood-cooling would probably help a lot but I can't say for sure. It's a pain to clamp down or mark on too since it's so slippery and as such nothing really holds it and ink can come right off. Drilling was fine, again just use low speed and make sure you have a good grip on the drill as it sometimes pulls and makes nasty hourglass shaped holes! You can shave corners with a knife quite easily which is handy for rounding things off without a load of filing too, plus 5mm or smaller bits can be cut using just a knife with a few passes but things like 8 or 10mm will eat up a lot of punishment.

Like I say, I haven't used it in the arena but it does seem to take hits pretty well from what I've seen. A lot of gouges and not a lot of actual damage seems to be quite common. There's actually a thread in the Beatleweight section about the advantages of HDPE against UHMWPE, so that might be a good place to look.