Not an expert on the old Alpines so I can't really comment on them. However I've had a 9883, a 9884, and a 9886. The main difference for the money between the 9883 and 9884 was IMPRINT capability. The main difference between the 9884 and 9886 other than 'fluff' seemed to be the voltage output. As far as I can tell pretty much everything in that line is substantially the same in terms of meaningful features (but with different price points) until you get to the 9887. It comes with time alignment, active mode, and 5/7 band EQ BUILT IN. Everything below it requires you to get IMPRINT in order to have that and more. I believe this new structuring of the product line is specifically done this way because Alpine doesn't just want to sell true audiophiles a head unit any more, they want IMPRINT kits flying off the shelves too. You can settle for the 'Best Buy' stuff or you can pony up another 100 or 150 bucks if you want more and another 1-200 bucks for the bluetooth module. They want to force you to pay for features on top of the head unit that other manufacturers are building in.
I too am now into Pioneers and Eclipses. You pay your money, you have the choice get your tuning features built into the head unit and you have the choice of deciding how a head unit with decent features sounds for you before you introduce a separate processor into the mix. With Alpine you get nothing more than over glorified bass and treble boosts (AKA bass engine and 2 band graphic EQ)
My pioneer premier DEH 980BT is 5 volts/channel, has Bluetooth built in, IPOD controls, time alignment built in, and 13 EQ with multiple savable pre-sets built in for the same price that I'd have to pay for a 9887. Alot of people here who talk about how much they love Alpine are dealing with stuff that isn't actually manufactured anymore, or just got hooked on the name because of how good it was back in the day. IMHO if you're really serious about this stuff and you're an SQ person there's nothing in their new line worth buying below the 9887 but quite a few things that aren't made anymore that are worth snapping up if you can find them.