I've posted once in this thread previously.
Dipping back in I noticed a post about which is the best unit.
This is an almost impossible question to answer. The best I can do is give the reasons I have my unit.
I dive an AP Inspiration Vision (although they have rebranded all the model names so don't ask me what they call it now).
Also, I started a long time ago, so there weren't that many units on the market.
I picked the inspiration vision because.
+ I live in the UK and its made in the UK, support both technical, spares and RTB is easy.
+ The units are well established, as is the manufacturer. So long term support is available.
+ The units are modifiable. Mine is not quite stock. All mine has is a backplate fitted in place of the standard harness.
+ When I stay stock, mine is an early version of the vision, so no bailout valve (very desirable), original handset (not the nice new colour one (which my eyes would prefer).
+ Running costs are low. Sensors are available from two sources (AP did have an issue when teledyne dropped out of the market). The current AP sensors are excellent, and this means AP are no longer reliant on a third party for there sensors.
+ The scrubber is do it your self, you buy the sofnalime and pack the scrubber yourself. Whilst there is a recommended grade, if forced to you can use an alternate - with the associated drop in run time.
+ The unit weight - was less than the twinset I was using. There are lighter units around now.
+ Scrubber duration. When I was first looking I had a number of choices. This had the longer scrubber running duration (note - scrubber runtime is depth dependent)
+ Cylinder size. Mine uses the 3 litre cylinders, You can now have 2 litre cylinders with the same scrubber (when I bought mine it was a 2 hour scrubber and 2 litre cylinders). The big advantage with the 3 litre cylinders, is that I can do a weekend of 'recreational' diving without refilling the cylinders. NOTE - the big issue is available bailout - so I either refill the DIL, or carry a bailout under this circumstance. In the early days, and even now, access to high pressure O2 can be an issue.
+ The units where tested to 100m+. And being dived in the UK to those depths.
+ The Inspiration is approved and tested for trimix use with thousands of trimix dives completed on it.
+ It does have full EU testing - which isn't really that important to most divers, but can impact legally on you in some places. Especially if you are commercial using the unit, instructing or diving. It can even impact on the ability to sell a unit in some places.
In truth I have been very happy with my unit. Other than the cell issue [1] that AP went through when Teledyne withdrew from the recreational market my unit has been very reliable. My handset died just before the new units where launched, so I have the original version. I do understand that there have been some problems with the newer handsets, but I would still have preferred the newer unit.
If I had the money to replace my unit I may well go for the JJ, but it would still be a bit of a toss up.
The main thing to consider is what do you want to use it for. How this impacts on the scrubber life. How easy is it to get the support if it goes wrong. What will you want to use it for in the future.
There are a lot of inspirations around, often, I can borrow, scrounge or beg for a spare, especially if on a trip.
Mine dropped off the harbour wall last year on to the boat, shattering part of the case. I was able to apply a few tie wraps to fix the problem - allowing me to finish the weeks diving.
There are after market travel frames that I could replace the case with - but I do quite like it. One day I might change.
Anyway, thats my reasoning.
Gareth
[1] I have to say AP where very good. There early attempt at mass produced sensors had early failures. I was back to back diving, they basically shipped me multiple sets of spares sensors. Strictly speaking if you returned a sensor under warranty they would ship you a replacement. In truth they shipped me half a dozen spare units, with me either returning defective sensors under warranty, sending back unused sensors, or paying for any i kept as spares. They had there problems - but they tried to support there users despite the technical problems they where experiencing.