I wrote this today for a Smogon topic stating why I believed Scizor should be moved into the uber tier.

Generation IV has been very kind to Scizor. With the addition of new priority moves like Bullet Punch, many slower Steel and/or Fighting types now find themselves with a potent new weapon. Scizor is no different. After fighting in 70+ wifi battles, I feel that there is just cause to consider Scizor to be placed in the uber tier. Let's look at a few main reasons:

1) Access to a powerful priority move. Bullet Punch is a staple on Scizor. With the ability to use Technician, Bullet Punch becomes a 60 BP+STAB attack. Considering that Scizor's attack stat can reach nearly 400 (close to that of Metagross), Bullet Punch is sure to cause severe damage to nearly everything that switches in against it.

2) Extremely easy setup. Because Scizor often forces switches, it is almost guaranteed a turn to setup Swords Dance. As I'm sure you know, SD, in effect, doubles Scizor's already phenomenal attack stat. Combined with Bullet Punch, Scizor is guaranteed a powerful attack.

3) It is very difficult to counter. The closest counter Scizor has against it is Infernape, but considering the lack of a fire-type priority move, Infernape will be severely damaged before being able to attack. Worst-case scenario, Scizor could just switch out to an Infernape counter due to its extremely easy SD setup. But the main point is that Scizor is only weak to one type (fire), but resists ten! Furthermore, Scizor has a fairly significant defense stat, enabling it to easily shrug the majority of hits or...

4) It has virtually unrestricted access to Roost. Roost was mainly intended as a healing option for flying-types, but the designers purposefully put in a hitch: the removal of flying types. Because of this, flying-types became vulnerable to EQ and fighting type moves on their Roost turn. This hitch does not, however, apply to Scizor because of it's lack of a flying-type. This gives it free range to recover it's HP without having to consider the possibility of a counterattack during the Roost turn.

The overall result of this is an extraordinarily powerful sweeper in OU. SD Bullet Punch combined with LO can decimate entire teams, but the presence of Roost prevents a typical LO stall strategy. Because I believe Scizor is such a monstrous threat in OU, compounded by the four reasons above, it would be in the best interests of the metagame to move it into ubers.