I use tropical, Placidus.
But that does not mean that only the tropical zodiac and quadrant houses are to be used. If equal houses or other similar systems give good results (for you), by all means use them. The same applies to the different zodiacs in use. They are, after all, nothing but systems of measurement which can be chosen arbitrarily (although I happen to agree with the philosophical basis of the tropical.) The tropical zodiac keeps the signs lined up with the seasons (signs have symbolic relationships with the seasons) while the sidereal zodiacs do not...Christmas can come in summer in the sidereal zodiac -- and what would the world do without a White Christmas? Only an Australian can imagine such a thing.
The various sidereal zodiacs (there are pehaps a half-dozen different ayanamsas) are all based on the constellations (fixed stars) and are most appropriate for those astrologers who take a physical or material view of astrology -- who think its causative energy streams forth from some certain place in the sky. The tropical zodiac, which is earth-centered rather than cosmic because of its point of origin (the vernal equinox as measured each year), is more suited to the humanistic astrologer and the abstract -- rather than concrete -- type of mind. The sidereal zodiac(s) relegate astrology to the distant stars, while the tropical brings it down to Earth. Both allow for precession; the claim by the siderealists that tropical does not allow for precession is bogus. And the Fiduciary for any of the sidereal systems is arbitrary, whereas the zodiacal point of beginning in the tropical system is measured each year and not arbitrary but real.
As far as house systems go, the attempts to adjust for high latitudes in the quadrant systems fail. But the reason is that such phenomena actually occur at the high latitudes. The difference between ecliptic and equator causes these difficulties, but they are real and not created by systems. The systems only reflect the reality. The symbolism of the equator is "mundane" and that is why it should be the basis for houses. The signs are "cosmic" and rely on "the stars" (not actually, but at least symbolically). That is why the "star" positions are given in zodiacal (ecliptical) longitude. The houses, unlike the signs, are not "cosmic" but "mundane." They do not show deep and immutable essential characteristics as do the signs, but instead show "immediate surroundings", "the worldly condition of circumstances," or adventitious or accidental occurrences. That is why they should be determined from the equator rather than the ecliptic. It is the transference, translation or projection of the equatorial into zodiacal terms that "produces" the distortion at high latitudes.
Different astrologers adopt different systems. All of the systems work to a greater or lesser degree, and astrologers choose a given system based on their own personality and proclivities. My own experimentation with the whole-sign types of houses did not suggest to me that they are superior, and therefore I continue to use Placidus (and in some cases Regiomontanus) houses. Other astrologers, such as Robert Hand and Dr. Farr, have found whole-sign houses to work very well and use them.
When I cast a horary chart, using Placidus, for an urgent question regarding personal death (in the middle of the night) and the person's natal 8th cusp (in Placidus) appears as the Ascendant, it makes me think there is something significant in that house system. No other house system gave me the 8th cusp rising in a question of imminent death.
That is the question to answer in choosing your house system: Does this system provide sensitive degree points that correspond to actual experiences in the life? I have found that house cusp degrees given by Placidus do often meet this criteria.
As far as the two primary planes of astrology go, both the horizon and meridian are primary. They form the structural basis of any horoscope, in reality. The whole-sign group of house systems generally ignores the primary importance of one or the other in the horoscope. I find this unacceptable; the reality and primacy of the Midheaven can't be denied. The calculation of the entire chart depends on the RAMC; to calculate the chart based on this position, and then to ignore the point (or put it into a position of secondary importance) seems illogical to me. The meaning of the Tenth Cusp is "That which stands above all else -- i.e., the king, the highest authority, that which is over the native, what is elevated in his life. That is the same meaning as the MC, and the two should be one.
But as I have said repeatedly, if it works for you, use it. Astrology, although it indeed forms a body of philosophy, should not be judged on its philosophical merits but on its ability to produce consistently reliable results when applied to real world problems.
Actually, the testing of the zodiacs is not that hard to do. You can set the same chart in both systems. This will, in most cases, change the house rulers. Where, for example, Mars is lord of the Ascendant in one chart, it may be Jupiter in the other. The question then is: "Which of these two planets best describes the character and life of this real individual? Which rulers of derived houses seem to more accurately describe actual life circumstances? It shouldn't take too many test horoscopes to find out which system seems to give the better result. Such testing, even though it tends toward an objective evaluation, must still remain primarily subjective. Like it or not, astrology contains a highly subjective tone and it can't be helped. This is at once the strength and the weakness of astrology.