Reliability: both are good, but the Vitara being more old-school (body-on-frame, part-time 4WD) is easier to fix when something goes wrong, and also more suitable to rough terrain, flooded areas (a snorkel is however strongly recommended if you're going to face floods constantly). The CR-V is way more sophisticated.
Efficiency: if you're talking about fuel-efficiency, I'd take a look at a 1.6L 16-valve Vitara with manual transmission, since the 3-speed TH180 automatic has a slippy torque converter and no overdrive. There are some with the 8-valve engine which, altough have the torque revving band at a lower point, often feel underpowered. There are some claims about the CR-V having better fuel-efficiency due to its transversely-mounted engine, but considering it's heavier and with a larger engine might not be too much better, altough its more sophisticated engine management may help to cut the fuel consumption.
Less fuel consumption: I still would take the Vitara over the CR-V. Anyway, if you didn't get so satisfied, it's easier either to convert to LPG or to perform a diesel engine swap
Engine power: the Vitara has enought power. It's quite low-geared, which sacrifices fuel-efficiency a bit in highway but leads to a better performance while driving uphill.
Stability: the CR-V, due to its more sophisticated suspension setup, wider body/axles and lower center-of-gravity, tends to have a higher stability. Also, the full-time 4WD setup enhances the grip in good pavement while the part-time setup of the Vitara is not recommended to use in good pavement.
Automatic or manual: it's all about personal preferences. If I would get the Vitara, I would rather get one with manual transmission. By the way, I don't even remember to have ever seen a CR-V with manual transmission, and its collumn-mounted shifter is pretty convenient.