The Kentucky Wildcats are almost certainly the best men's basketball team in the country this season. They'll probably lose at least 1-2 times before the season concludes, but their track record emphatically states their case. That UK is the best basketball team in the SEC is straightforward; it's far harder to suss out which teams are next in line.
The quality of men's hoops within the conference has improved this season. For example, last season KenPom only had three SEC teams ranked in his Top 40, but so far this season there are five with a sixth (LSU) ranked 41st. The explanation for the league's improvement largely rests on the shoulders of the mid-tier teams. The middle of the pack has demonstrated the ability to achieve upsets on any given night this season.
The lack of a few teams distinguishing themselves could eventually hurt the SEC's postseason presence. The SEC could cannibalize itself away from receiving more bids to the NCAA tournament. Losing at home to a conference opponent that is itself on "the bubble" only makes things harder, and that could definitely happen more than a few times between now and March. It could also mean there's a lot of chaos on the horizon as pecking orders will be in constant flux, which could also be a lot of fun.
The second tier appears to be the following schools (rankings as of January 21st):
A common rule of thumb is a team almost always has to be in the Top 60 in RPI to even have a chance to receive an at-large bid into the NCAA tournament. Several SEC teams look comfortably in that range for now, but many of these teams will be playing each other - in some cases twice - over the rest of the season. Unless they get hot, Ole Miss and South Carolina likely will not be making the tournament given the tenuous grasp they have at the moment. Florida doesn't seem to have an identity outside of a gimmick full-court press, Alabama's best win is currently Tennessee, and Texas A&M is still coached by Billy Kennedy. I think all of these teams are currently on the outside looking in, but just barely.
The teams that seem the most likely to make postseason play are probably Georgia, LSU, and Arkansas with Tennessee as a dark horse. Georgia is an experienced, well-coached squad that has a star in Marcus Thornton. The hardest part of UGA's schedule may also be over. The 'Dawgs still have two games against UK, and a few potential road games that could cause them trouble, but they look control their own destiny at the moment. If they don't make the tournament their non-conference loss to NIT-bound Minnesota may loom large.
LSU is playing well at the moment, and likely has the second most talented team in the SEC. The Tigers' front court will challenge any team, including UK. They won at West Virginia and have beaten UGA. This is another team that looks to be on the inside looking out, and has the ability to make a deep run in the SEC tournament to cement its status. The loss against CBI (if that)-bound Clemson could hurt LSU if they drop in the rankings.
Arkansas probably also makes the tournament, but they'll need to bounce back quickly from their two loss streak because several teams are nipping at their heels. What will help out Arkansas the most is the seven remaining home games are likely going to be at least six wins. The remaining seven road games feature three games against Mizzou, Mississippi State, and Auburn which are arguably the three worst teams in the SEC.
At the moment, I think Tennessee qualifies as a dark horse to either make the tournament, or at least get one of the play-in games. The second place team in the SEC has a nice win against Arkansas and has taken care of business against lesser foes to this point; however, the schedule is about to get tougher with a game at Arkansas, two games against LSU, at UGA, at Ole Miss, and host Kentucky. Can the Volunteers hold on?
While those look like the most promising contenders at the moment, the other contenders just on the outside have proven capable of winning their fair share of games. Alabama, Ole Miss, Florida, Texas A&M, and South Carolina remain dangerous to any team in the mid-tier, and Arkansas and Tennessee appear especially vulnerable to being surpassed going forward.
The safest bet is to assume there's going to be more chaos, and that several teams will probably need strong SEC tournaments, or participate in the play-in games in Dayton, to help their odds to make The Big Dance. At the end of the day, the SEC is not inept at men's basketball compared to previous seasons, but the lack of more teams in the top tier with UK holds the league back.