Good to see that Legere have finally come up with a sensible reed - a few years ago I bought a 2.5 Legere original alto reed and it was stiff as a board, certainly a lot harder than their strength chart would suggest. Then I got a 2 Legere Studio Cut and it was the softest reed I'd ever played - like a Rico 1 (or a Rizla Blue?) - a lot softer than their reed comparison chart indicates - I like a flexible reed, but this was ridiculous. So I gave up on Legere and went on to Fibracells. If I'd found the right strength I'd've stuck with Legere.
I'm tempted to give a 2.25 Signature a go, although those Forestones also look interesting
I've tried a few synthetic reeds -
Bari plastic S - very V shaped cut and very bright - ok if you want to sound like John Zorn. My first one was cut off-centre, I emailed Bari and they sent me 4 replacements, all of which were cut slightly differently - full marks for customer service, low marks for consistency and quality control. They're made out of quite a hard plastic, so you can file them down with a bit of effort. Not tried the Bari Star reeds
Hahn - I've had several of these - 2, 2 1/2 and 3, responsive and bright with lots of zing, but the fibres tended to delaminate and stick in my lip and the tips went all tatty which made tongueing a bit awkward. The stick on rubber pad serves no useful purpose. The 3 was too hard and didn't get much use. In general I think synthetics are better for people who like softer reeds - they don't go all soggy like cane
Not tried the Hartmann - heard good things, but a bit put off carbon fibre after the Hahn - I saw Evan Parker using one on soprano a few years ago, so they must have something going for them
Fibracell Soft - the transparent film on the flat side of the reed tends to bubble and peel off and after about 8 months they tend to go very soft and die on you without much warning, but other than that the best so far. You have to be careful not to damage the tip, or it's £14 down the drain
I think the Legere Signatures will be good - they're made from tough durable plastic rather than laminated fibres, so won't have some of the problems mentioned above and will probably last longer than the Fibracells.
They've certainly had positive reports from a lot of people who aren't normally fans of synthetics - you wouldn't expect orchestral clarinetists to be seen dead with a plastic reed, but there's plenty of them endorsing them on Legeres website. Mats Gustafsson previously used Fibracells before he moved on to Legere, which makes me wonder if they're better for the kind of noises I make.
I'm just a bit reluctant to spend 20 quid on a reed and it might not be the right strength - previous experience has made me wary of their reed comparison charts, so I'd value the opinion of any alto players who use Legere Signatures as to how they compare strength-wise to normal Ricos and Vandorens