Not noticed any crackling with the Solina.
The Matrix suffers from not responding well to Note off in both standalone and plugin. Seems to work OK when used with a midi stream within SONAR. This problem has been reported to Arturia and has been escalated to the development depart by the support person I have been communicating with.
I am surprised at the cost as I got the upgrade for £99 with some gentle shoving. Though I do own standalone licences for the Modular V, ARP 2600 V, CS 80 V and the Prophet V along with the V 3 collection licence.
The SPARK 2 that comes with 4 is very different than the SPARK VDM that came with 3 as it would appear to have more of the SPARK kits not just the vintage drum machines, it has SPARK Factory, SPARK 2 Factory, SPARK Vintage, and some/part of the EDM and Hip Hop expansion packs.