I'd say that while there are periods when we afe good defensively, on the whole we're not a good man-defense team when we are playing a good/strong opponent. That is when you see the problems.
First, we have guards and forwards who, when man defending on the perimeter, often get beat off the dribble, and when that happens your defense has immediately broken down. Good players on good teams beat our players off the dribble a lot.
Also, our perimeter players tend to switch too easily when confronting a pick--you should always work to get around the pick and pick up your mark, if you can. Reason: if you switch, then you've given your opponent a mismatch--which is the very point of picking in basketball. You want to avoid mismatches.
The other fundamental mistake we make is that, if we do get caught in a pick and switch, we don't look to pick up our man again if and when the opportunity arises. The opportunity often does present itself, and the UT player who has switched should take it to jump back on her original mark, thus negating the mismatch.
Also, we don't seem to communicate as well as we should, and thus our help defense is often late. A good man defender, when her mark does /not/ have the ball, should have one eye on her mark and the other eye on the ball and the rest of the defensive area. In this way you can spot a defensive breakdown and react quickly enough to get over and help. Court and ball awareness are a big part of team defense and team defensive help. If you're just looking at your mark, then you don't see what's going on with the rest of the players and will be too slow reacting to a breakdown to help.
The best man defense teams naturally have a group of players with the basic quickness and tenacity to man defend--and the are also, as a group, very quick to help, so that the opponent gets very few clean looks at the basket.
I wouldn't say that these are a strength. When we play good opponents, our pattern is to have maybe one quarter when we play good defense but at least two when we are not good defensively--giving up about 20 points or close to it--and 2+ quarters of poor defense will get you beat.