Is there really much difference between (all carbon) booms? They are a pretty simple contraption.
I'm looking to buy an all carbon boom.
different shapes, heads, tails, profiles and of course stiffness. just depends what your preference is and what type of sailing you do.
It's all in the detail Panda - I suspect the carbon construction is pretty different from manufacturer to manufacturer although for overall strength you could'nt go past a Maui Sails carbon.
Of the ones I've used the quality front ends were- Maui Sails, Severne (which are Aerons), Neil Pyrde (although plastic was prone to cracking & don't know if they've fixed issue though).
Boom grip is nicest on the Aerons / Severnes, with NP a close second. M/S grip is pretty hard and is prone to peel away / lift at seem joint so this probably their only negative.
head profiles between ali's and carbons differ i.e. not as rounded at head which can feel slightly awkward initially.
All that said my brother still has an old Autima carbon boom (about 9years old now) that has had head replaced about 4 times and had a large amount of abuse but still going strong as ever. I used it for about 4 years and he's just started sailing again - I'm 93kgs he's 120kgs 
Yes.
Just like not all alloy booms are built equal, not all carbon booms are built equal. There are differences, but luckily booms are something that it's quite easy to pick it up and judge the performance without having to demo it.
One's I've used:
- Streamlined, the boom I use currently, I think this is the stiffest boom on the market, also probably the lightest, I think only a few booms i.e. severne enigma may be lighter. Downsides, not supernewskool thin boom grip, its 28mm, some new booms are down to 25-26mm. Front clamp is bulletproof, but a pain in the arse to adjust, also doesn't have loop 'n' go back.
- Chinook, older ones seemed a bit spaghetti, at least compared to my streamlined. New ones seem better, used one for 2 weeks in maui, could basically be described as 'a boom'. Won't particularly impress, but don't think it will disappoint either, grab one if you find it for the right price. A bit heavy, pretty stiff, nice shape easy to grip front of boom in transitions, hardware (clamp/tail) work fine. For some reason thou seems to have a tail piece set up for an adjustable outhaul? I dunno wave booms should come with a loop'n'go back end like the norths do, best system imo.
- Severne, newskool super thin grips, 26mm or 25mm if you go enigma. Redline seems similar to the chinook in terms of weight, hardware (thou without the odd tail piece) etc, but with the added benefit of being really thin. The enigma is also fairly light, maybe a bit lighter than streamlined, but trade off is it's not the stiffest boom on the market. I'd probably get a redline boom if I got sick of the overengineered front end of the streamlined.
That said, seen a lot of nice booms from the likes of simmer and aeron as well which are well priced, but haven't had a chance to try them. You should be able to pick up a nice carbon wave boom new for $800ish. This is why I haven't mentioned NPx9, as it's pretty much the boom you buy if you still have some weird belief that expensive = best, at $1200ish it's obviously the best if you wanna judge booms off the dent they make in your bank account.
A wave boom.
I was seriously looking at the Severne Enigma but it is just slightly too short for my largest sail, by 5cm. Damn it. Redline is next on my list but I wanted to consider a few others too.
Have noticed my NP X6 has cracks on the plastic, but that's a few years old now. Perhaps they've resolved it since. I did break the tail end but that was very likely low tide's fault. (ouch)
I do prefer the thinner booms, my very first was thick and the difference is very noticeable.
A Chinook I owned once was heavy, but felt indestructable.
I've just realised this will be my fourth boom.
Still leaning towards the Severne Redline...
if its for wave just wondering why carbon?
there are plenty of super strong and cheap alu wave booms around. I use a Severne blue line for wave and they are solid as hell. Also you can throw the alu ones around alot without worrying about cracking them.
Im not sure on availability but one of the best carbon booms Ive tried was an X-booms carbon slalom that my mate had. It made my fairly new Chinook carbon feel like cheese. It definitely put a hole in is bank account though lol! 
the new chinooks arent very heavy at all in my opinion. nice grip, good head and made 100% in the Gorge. I recently did a tour of their facility and was pretty impressed by the setup.
Why carbon? Because I can. Looking to keep it for many years and I've got this theory about saving a dollar and paying twice.
Ah yes, a wave boom, but mainly for sailing in the bay with wave sails. 6.3 & 5.5 on a 105 FSW. Actually I've used a 6.2 in an onshore seabreeze, quite a bit on the Cold Toast. It was OK for blasting around in the surf.
Still leaning towards the Redline. Doesn't sound like a poor decision. Thanks all so far.
Get an AL360! Stiffest boom on the market, moulded holes in the tailpiece, v-grip, bombproof front end and available in many sizes.
I've used Pryde x5, x7 and x9 in the past, also Fiberspar All Carbon and a couple of Chinooks. None of these booms even comes close to the AL360 if you compare stifness and quality. Also tested the 2012 Pryde X9 and Unifiber carbon, both booms feel looser/ less stiff than my 4 year old AL360 boom.
V-grip you either hate it or love it. For me took a couple of sessions getting used to but won't change back to a regular boom again. It's easy to grip, no need to squeze and you don't get sore hands after a day of sailing. In fact in the 4 years i'm using the AL360 i've hadn't had any blisters on my hands.
