Spaghetti has first hand knowledge of a lot of spearguns, esp. the wonderful Italian brands. I am quite excited by the Omer range of products, have heard good things about the Excalibur...which is the one I would look at. There was a thread last year where one forum member did not like the T20 -- I think maybe they owned Excaliber & T20...might be worth doing a search (although it seems harder to find old threads these days).
I would check out Spearo.co.uk as Dave always has an interesting range of spearguns. I like the look of the Seatec range (I think Seatec was started by the guy who started Omer) & C40. - both offer "cuttle fish" shaped barrels for easier swinging. He carries Rabitech now too:t.
I have good things about the Imersion spearguns. I believe Neil at Apnea.co.uk uses one himself. He also carries the Omer range for the UK. Don't know about the model you mention. The difficulty swinging a longer gun is a legitimate issue to resolve -- swinging a 90cm gun quickly just doesn't work. That said, perhaps the issue is more about picking the right length gun for the job. I have had trouble swinging my 90cm speargun on a fast moving bass BUT I was fishing gulleys ... a short gun would clearly have been a much better choice for that. In open water & normal range, not so much of an issue.
The Omer American Master is expensive in the UK
-- but does look & sound wonderful. How about the new XXV & XXV Gold spearguns - anybody know anything about them?
I have only handled a few spearguns. Mine is a 90cm Rob Allen Sparid railgun and I am completely happy with it. The handle looks & feels good. I like details like the muzzle design, its bungee & clip & the handle clip. It feels solid, powerful & it is accurate. I handled a Cressi Commanche in a store. Spaghetti is right feeling them in your hand makes quite a difference. In pictures, I thought the Commanche was easily the best looking speargun around. Seeing and handling it, I got a completely different impression. First off it looked & felt much smaller & lighter than I expected -- this is neither good nor bad, just different. The handle was very slim, it would be great for somebody with small hands but it was not uncomfortable for me. The lightness was probably due to a smaller diameter barrel tube than I am used to and a smaller diameter spear -- it felt a little flimsey to me but I am told they are quick handling & the slim spear fast - and I believe it. It had little plastic clips on it at the side on the barrel, for which I can fathom no reason (alternative line releases?)...I really didn't like that at all, mainly as I have a terrible habit of absent mindedly snapping plastic clips and, although I look after my gear, I expect it to be tough enough not to break on me. Being light, it might be a good choice if you are moving up a size and people who own them seem to love them. I really like the Italian spearing products I have seen so far. I am not sure if PO are carrying Commanche any more -- they were getting ready to stock up on Picasso when last I was there (the Centuary will probably be the model to compare to the Comanche).