Flexi should handle transparencies good too since 10.5, since they use the PDF-RIP-Engine ... as long as you just link the PDF to the editor or put PDF's directly into the production manager.
Pixelblaster: I'm working as a Supporter for a SAi-Dealer and I'm a little bit surprised about the statement that the software is not available in the US because we (in Switzerland) have started selling Pixelblaster a few months ago, and we have sold it until now 3 times bundled with some HP Latex-Printers. Perhaps not all of the SAi-Dealers have adopted it? We start selling it mostly for customers who wants to have a mac-rip.
Pixelblaster can't be directly compared with Flexi, because Pixelblaster is no Print & Cut-Hybrid (for vinyl cutting jobs), it's just for Printing and Contour Cutting. Pixelblaster is a suite of applications for finishing, RIPping and printing. The Frontend is a really cool PDF-Editor, something like a small Illustrator, but with multi-page-editing possibilities, a very special tiling tool with much more functionality than Flexi, a banner finishing tool with the possibility of placing marks for grommets or mirroring borders and so on, a serialisation-tool with more functionality and more flexible usability than Flexi, a really enhanced template-feature suitable for print-job-processing, a true shape nesting-feature and so on. It proofs files too for things like enbedded profiles or not, special items (Spot Colors etc.), multi-pages and so on. Until now, Pixelblaster is our favourite PDF-Editor because the Editor can handle issues for example with non-embedded fonts Illustrator can't do. Cut Contours are handled by layers which could be set to cut-layers, and in opposite to Flexi Pixelblaster supports not only Summas OPOS, but OPOS XY and OPOS Barcode too.
The RIP-Application itself is PDF-based and offers Queues for Contone-Proofing (CMYK-Simulation), Photoprint (max. gamut), 1-bit-Proof and Separations for Screen Printing. It sends data as soon as it started ripping, what is really useful with the latex-printers who needs to warm-up.
An interesting feature is ROOM (Rip once, output many), with which the files will be saved after ripping. An additional tool allows placing numbers of ripped files in multiple copies on a workspace and print then.
Additional applications are the profiler, a media manager and so on. It comes with a network licence, but without dongle: if the computer on which Pixelblaster is activated is available in the network, Pixelblaster can be used on every PC and Mac in the network. It is scalable because of the possibility to share print queues over multiple RIP-Servers for relatively small upgrade-fees, multiple licences of the editor can be used and so on. It is usable for special colour-printers by the possibility to define every single color channel.
A little bit disappointing is that they don't deliver profiles for most of the printers, with the argumentation that the philosophy of the software don't allow that (it needs onsite-calibration for contone-proofing over multiple different printers work). I do profiling myself too without problems, but it was hard to do profiling right from the scratch with a completely new software.
I like the software. There are still a few bugs, and I still sell FlexiPro because it's a different software for different users , but if you have the possibility to have a look if someone who knows the software using it for tiling, nesting and so on, take the chance.