Charles Daly lost the Bul distributorship and then IIRC went out of business. Angus may have picked up some of their old stock or May have purchased some from Saul.
Saul Kirsch ran a Bul in top level IPSC comps for a number of years:
http://www.doublealpha.biz/ He is now shooting an STI IIRC.
The original Kimber polymer framed 1911 was a Bul that was relabeled. AFAIK they now make their own frame.
Buls are a cut above the Para and a step below the STI Edge for standard division. Several of my friends own them and have high round counts, none have had to replace internal parts. Several of my friends have also bought Paras and have had difficulties either out of the box or with parts wearing out prematurely (Prematurely being within 20,000 rounds, which is not a lot for an IPSC shooter). My Para was a POS when I bought it second hand and became worse after a gunbutcher tried to fix it, so I am biased against the brand.
I run STI mags in my Bul, so mags are not a problem. Apart from the trigger bow and mag release I don't think there are any non standard 1911 parts.
Good luck with your CZ, they were popular in Australia for a few years until a problem developed with the rear sights cracking under recoil. The Springfield P9/Tanfoglio/Witness also had issues with cracking of slides and broken slide stops when loaded to major. There have also been reports of slide stops breaking on CZ SP01s. It appears the CZ design is rather borderline with high energy loads. I would rate the Bul several notches higher on a durability scale, but the CZ is certainly a sweet pistol.
Realistically the Bul is not a good option for open as it does not have a steel dust cover to mount the optic rail on. You would either have to run a slide mounted optic, with the usual problems of losing your sight picture in recoil and of recoil destroying the sight, or mount it the position of the take down lever, meaning you would have to sight in every time you dismantle the gun for cleaning or transportation.
Things I have noticed about the Bul:
Trigger pull from the factory was a tad over 3 pounds and crisp.
The STI mags needed a smidgeon sanded off the front to ensure they fit in the Bul mag well.
Original Bul hi cap mags worked fine in my Bul M5, factory 10 rounders were not available when the law changed in Australia.
If you maintain a death grip on the gun when using STI mags it can prevent magazines from dropping free, the polymer frame is not as rigid as the STI 2011 frame.
The grip is not as large as the STI grip. If you have small to medium hands the Bull will be better, the grip is slightly smaller than the Para.
The mag well is aluminum, so it gets nicked up fairly rapidly.
The rear sight appears to be an LPA adjustable sight, the front sight is dovetailed and has never worked free.
The gun is very reliable, when held with one finger and thumb it still cycles a full mag in rapid fire without a hiccup.
The oversize mag release is a little too large for me, as I am left handed it rubs against my trigger finger.
....
screwed with the beretta option ATM, and i'm not convinced it's as tight as a race gun, or let's say a great prodie gun like the SIG X5 is...
...well,well!! ...here i go again with this in mind: pimped 1911 or service guns 
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