For real 4 season use, I think the best is MOSS. Try the Titan model as it is the best compromise of weather protection, warm weather versatility, ventilation, space to weight and comfort, that I have seen. MH tents are very good as are Marmot.
Unless you are planning to use for altitude/arctic conditions most of the time, avoid buying TOO much tent. Some companies market their tents as 4 season because they stand up well to snow loads, cold weather, etc., but they are truly ONLY good for these conditions and should be called cold weather tents. A key red flag is anything with the term "summit" or similar in the description.
These tents are almost always sweltering in even the mildest summer weather, and do not vent heat well. Also, the floors are often too lighweight for camping on rocks, sticks etc.
If you only camp in spring summer and fall, get a good three season model
Otherwise, if you are camping in all four seasons, get a top brand and make sure their idea of four seasons is not winter, winter, up north, and summit.
For quality sake, go with Moss, Marmot, Mountain Hardwear, TNF, or Sierra Designs.
(I still think you'll be happiest with the Titan!)
Also, checkout Backpacker Magazine's Gear Guide Annual.
Things to consider:
SIZE - Don't carry more than you need, but don't be cramped either.
VENTILATION - how much mesh? Windows? Vents?
POLES - Aluminum T7075 is best, fiberglass braks in the cold
POLE CLIPS OR SLEEVES - Clips provide ventilation and easy setup, Sleeves are stronger.
FLY - Dark flies make for gloomy interiors on rainy days. And are hot in the sun. Full coverage is important for wet and windy weather. Is vestibule big enough.
CONSTRUCTION - Strong seams, heat taped, thick floor w/good waterproofing, guy tie-outs, self standing.
AND MANY MORE...
Hope this helps.
Jet