I'm assuming you're comparing the two because you're considering buying one of these two cars, so I thought I'd try to offer my own opinion since I have owned both a Nissan Pulsar and now recently bought a Mazda 3.
Value for money:
Mazda 3 Maxx Sport (5 sp Manual) - RRP $25,655
Nissan Tiida ST-L (6 sp Manual) - RRP $22,240
For Mazda I think the Maxx Sport is the best value of the 3 2.0L models, but obviously not the performer of the SP23 which definitely can't be compared with the Tiida (I think the standard Mazda 3 is also a step above the Tiida). Though the Maxx Sport has features that you could do without if you are sensitive to cost.
Maxx Sport comes with 16" alloy wheels compared to 15" alloys on all the Tiida's. One thing I don't like about Mazda is the "space saver" wheel, which is like a thin wheel that you can temporarily use on your car, while the Tiida has a full sized steel spare (still ugly). After getting the number of punctures I used to get in my old car, it was useful to be able to use the spare for a day or two before taking the other one to get repaired!
Fog lights and spoiler are only available in the Q for the Tiida, and Maxx Sport comes standard with fog lights and a weird spoiler that doesn't have any space between it and the bumper (just sort of sits on top). There's a whole bunch of other unnecessary crap too - like sideskirts, 6 speaker stereo and things on the Mazda. I like the look of them though & it adds to the value for money aspect.
Performance:
Mazda 3 (all 2.0L models) - Max Power = 104kW @ 6,500rpm
Nissan Tiida (all models) - Max Power = 93kW @ 5200rpm
Mazda 3 handling is way better than my Pulsar - probably similar for the Tiida too...
Fuel Consumption:
Mazda 3 (all 2.0L models) - 8.6L/100km
Nissan Tiida (all models) - 7.6L/100km
Roominess:
Mazda 3 is really comfortable in the front seats & squishy in the back (looks bigger than it feels when you're sitting in it). The back feels like there's more cushion than sitting space. Mazda 3 has bigger dimensions outside but you'll need to check out the inside to see for yourself. No idea about the Tiida.
Safety:
Mazda 3 (all 2.0L models) - Great - nice solid body. The ABS saved me hitting a car (who turned right from the left lane in front of my car), but didn't stop a car from hitting the rear. In the end, there was a rear impact bar that prevented any significant damage (other than bent metal, paint damage and bent plastic). Has 6 airbags (2 front, 2 side, 2 curtain) - thankfully haven't had to try those out yet. The tiida has 2 for the ST model & 4 for the others. The appealing factor in safety that made me go for this was the overall strength of the body compared to the Nissan Pulsar.
Nissan Tiida (all models) - ?? - I checked the ANCAP results on the NRMA site, nothing seems to be up. If this car truly is a 'new' Pulsar it probably has some of the same flaws (not too sure). The main thing was the crush near the driver feet if the engine dropped down in a crash - this would crumple the feet area by over 20cm from what I recall, though head protection was considerered good.
ABS is standard in both cars - (In the Pulsar N16 i test drove they was really loud and clunky. All ABS brakes (from my experience) clunk whenever they're used but the Pulsar was just louder). Maybe try the Tiida's brakes out when you test drive?
Theft:
Both have immobilizers but beware - if you lose one of these (2) keys they're about $300 to replace.
As far as I know, the cars don't come standard with an alarm, but you can get one put on. I got one during Mazda's M-Day sale for 'free' (obviously not that free), but the problem is it's REALLY sensitive - if a loud car goes past it will activate - If I drive it into the city I have to park in a carpark.
Reliability:
Mazda 3 - so far so good. New car so there's not a lot to say. Mazda have a reasonable reputation for reliability. My sister has an older Mazda 323 and hers has been fine. Just make sure if you buy this car you get them to upgrade the software so you don't have the problems that I've had (above).
I have a 7 year old Nissan Pulsar Plus (Series 2, N15). I never had any problems with it whatsoever. As long as you take it in for its due service, the Tiida should be similar. They probably just took the N16's 1.8L engine and put it in the Tiida.
I think both have a 3 year 100,000km warranty.
Final Verdict:
If you're REALLY tight for money, you can go for the Neo without all the fancy extras and you'll still get the performance of the other Mazda 3's for a manual RRP $20,790, but I don't think it's as good value as the other Mazda 3 models - doesn't come with ABS standard but you can purchase a 'safety pack'. If you want thxe power windows more than the other you can purchase a 'power pack'. I think those packs aren't good value though. There's not a lot of difference between the Maxx and the Max Sport other than the wheels & trims. The cheapest Tiida, the ST for a manual RRP $19,990 comes with ABS & Power Windows standard. I guess it depends what you're willing to spend rather than which is better - cause the Mazda 3 wins in that direction.
