To be honest - its hard to say as very rarely do two tag teams get any length of time to put on a match or any kind of storyline so I'm only basing this on what I have seen of them in ring on Smackdown/Superstars/NXT etc
Kofi Kingston/R-Truth
Everyone knows about their in ring abilities and faults. Kofi is decent in the ring but sh*te on a promo. Truth was a very good heel and a very average wrestler, now he is back to being a face he has kind of lost it again. But if they get a tag team name/same intro music etc then I could believe them as a worthy enough tag team.
Uso's
For obvious reasons, they are the most natural tag team about at the moment. I think they are solid enough in the ring and have a wee bit of personality, never heard them on the mic, only in backstage segments but they appaear a bit dull when speaking. They had a really good run of matches against Slater/Gabriel at the end of last year
Epico/Primo
I enjoy watching them in the ring, I think they are both technically ok wrestlers. Was looking forward to see them come out of their shell when they won the tag championships but we barely seen them. I think given enough time, they could put on some really good matches.
Titus O'Neil/Darren Young
As a tag team, I haven't seen a great deal of them as they aren't long together actually. In the ring, I think both are very raw. However both seem to be a good match for each other especially in any back stage segments/promos I have seen. They both have such weird personalities that they are actualy very entertaining to watch outside of the ring. Hope the in ring stuff comes with time as well
Hunico/Camacho
Yesterdays match was only the second time I have seen these two as a tag team. I think they 'look' like a tag team in the sense they have the same image/clothes/music etc. Hunico's in ring stuff is very good I think, Camacho I'm not sure. I would like to see more out of ring stuff from both and more in ring from Camacho to be fully convinced.
Reks/Hawkins
Personality wise these two are tremendous, bags of entertainment and remind me very much of Edge and Christian in that sense. In the ring Hawkins is decent enough and Reks is...well a bit sh1t. I'm not sure what has happened to them of late, I know Regal 'fired' them both from NXT so I had expected them to show up perhaps on Smackdown in the last month.
In summary - I think there is potential there in the division for both producing good in ring matches and for the out of ring stuff. But unless WWE properly invests in the matches and gives them a decent amount of time for matches and for storylines then it will just fall apart again and appear boring without allowing their charcters and in ring styles to develop