What year and model Impreza?
This is an odd grouping of cars.
New Beetles are newer (didn't come out until '98 IIRC) but are definitely the least reliable.
Integras are good (I used to own one) but cramped for taller drivers and are noisy and buzzy down the freeway. Reliability should be very good, but will depend A LOT on how the previous owner maintained it. Many were modded, and a lot of were beaten on by younger drivers, so buyer beware.
Any CRX out there is likely to be old and have high mileage. They stopped making them in '91. I used to own one of those too (back in '94-'95). Extremely reliable if properly maintained, but anything less than the Si model will be very underpowered (but 40+ mpg!). As a CRX is more or less just a 2-seater Civic hatchback (with some minor asthetic changes), it would probably be just a better idea to get a Civic.
Imprezas came out in '93 and maintained more or less the same body style until '01. The "new age" Impreza came out in '02. '93-'01 Imprezas came in a lot of different configurations, from coupes to sedans to wagons, and in 1.8L, 2.0L, 2.2L, and 2.5L engines. There are even some rare turbo models in the earlier years. All are likely to be very reliable, but some do have their quirks. Of the early Imprezas, the '00-'01 2.5RS is best, but will also cost the most.