Here's another 'thoughts' thread. I've already made a 'mistake' or two in the unlocks I've picked. Not that the unlocks are bad, just not really useful given what other unlocks I've already taken. So, for anybody considering picking up things in the recon unlock tree, here are my impressions on the unlocks I've got so far. And feel free to post your impressions of the unlocks you've taken. Hopefully we can advance through the game a little wiser from each other's experiences. Personally, I want to find out what people think of the support kit's sensor thingy.

RDX (Level 1 spec-ops unlock)
Item slot

2142's C4. It looks a bit like C4, it blows up like C4. I haven't noticed it being any more powerful than C4 particularly. Fastest way to take out a Titan's consoles or core are with this though; 5 C4s on a console and it's down, reload and move onto the next.

APM: Anti-Personel Mine (level 1 sniper unlock)
Item slot

It's a claymore from BF2. But I've found that since 1. you aren't obviously a sniper like you are in BF2, 2. not everybody playing is going to be carrying it, and 3. there's more ground cover on the maps, it's not expected as much and it's easier to hide. Plus the mine warning indicator isn't as obvious. I've gotten a few kills using these as booby traps when they would have been noticed in BF2. Still, I'm not convinced it's really worthwhile carrying these, since they take up one of your two item slots. If you have it, RDX is the better choice for the discerning explosives maniac.

DysTek Hi-Scope x4 (Level 2 sniper unlock)
Scope slot

It's a 4x scope for your weapon. You can zoom in much further than with the default scope and you can zoom in and out with the mouse wheel. This isn't strictly necessary since the big limitation on sniping tends to be that zooming in doesn't increase your draw distance. The other downside is that changing between zoom levels is a little slow. This scope also has a built-in rangefinder, not sure if the normal one does too.

Gruber 5 Stabilizer (Level 3 sniper unlock)
Item slot

Don't leave home without it. Sniper rifles in 2142 have laser accuracy, which takes away the head-scratching 'I know I should have hit him' you sometimes get in BF2, but gives you sway to deal with instead. This is very handy for dealing with those ultra-long range shots, and makes you lethal all the way out to the edge of your draw distance when combined with the 4x scope.

Zeller-H Advanced Sniper Rifle (Sniper rifle unlock)
Weapon slot

Hide. This is the Big gun. I like my big gun.

This gun will splat your brains out from the other side of the map. If you aren't wearing heavy armor, this weapon is a one shot kill. If you are wearing heavy armor, you certainly aren't going to survive a second shot, a short fall, or a butterfly flapping its wings at you. You don't lose your scope between shots, but it takes about a second to reload so if you've got one shot off and the other guy is close it's sometimes best just to whip out your pistol and finish him off that way. The other thing about this gun is the sway is very minimal and it has almost no recoil; you won't need your stabilizer for anything but the hardest shots. Watch your ammo though- it always seems to need reloading at the most inopportune moments.