Don't think I've seen a deal on V4 lightstrips before, though prices definitely aren't as good as V3 yet.
JB Hi-Fi also has V4 on sale for $107, making it $90.95 if you've got gift cards from the Coles sale.
Differences between V3 are addition of Bluetooth, there's a cut end connector included, and a smaller 6-pin connector see comparison.
Haven't found any way to mix-and-match V3 and V4 lightstrips yet, Litcessory is working on it but it won't be available for another few months. They've also noted V4 seems more delicate:
One issue we noticed during product testing is that the solder contacts on the V4 lightstrip connectors are very delicate and easily prone to separation with excessive movement. We caution being very gentle during your project installations and take care to provide proper strain relief near the connector housings.
Another issue we noticed is that the resistors are very temperamental and prone to burnout in both the lightstrip and controller with any power fluctuations. We advise to connect and install our products only when the lightstrip has been powered off.
Are kids still crazy about lightstrips for their bedrooms, or has the fad passed?