I find Nova very useful in soloing, but you have to pick your mobs wisely.
My preference is a large pack of Nemesis found throughout Peregrine Island. Minions come in packs of as many as 10, prehaps 12, but I don't recall if I've counted any minion mobs that high. I look for mobs of even con to a max of +4.
I'm in constant stealth as I approach the mob. Before I charge in, I prep with hasten and conserve power first. Then, as I am rushing in, I am using buildup AND aim, both of which are activated by the time I reach near the center of the mob.
I activate Nova and maybe - MAYBE - I've missed one or two. I pop a blue and with conserve power I take out the lucky Nem or two who didn't get hit with Nova. If they get hit with Nova they die every time.
That can result in as much as 8K - 13K experience (approximated) with one attack. At worst, the survivors get off an attack and I may take some annoyance damage, but it's a low-risk tactic with a high reward IF you time it right, which is very easy to do.
While Nova is recharging, I still have CP and hasten activated, so I reactivate stealth (which is recharged at the exact same time the Nova endurance penalty expires, so I'm in good end shape at this point) and kill some smaller mobs with lieutentants just to keep the XP rolling in until the death machine is ready to rock once more. With three damage enhancements, buildup and aim, it does more damage than I need. With the three increase attack rate enhancements and hasten, it's recharged in no time at all.
I've been doing this since level 32 with large mobs of minions and I have never hit the pavement in the 10 levels since. Just stay away from mobs with bosses or multiple lieuts. That's trouble, especially if you miss the boss who will proceed to pound you before you can pop a blue in an attempt to use a power to get away.
With regard to the usefulness of Power Push, I find it's greatest use is to allow me to use snipe in the middle of battle without fear of interrupt. In a solo situation, it only works if you are one -on-one because the other foes will interrupt the snipe. So, after I've offed the minions, the remaining lieut or boss gets a face full of Power Push and stands up to a snipe blast in the forehead. With Haste, I can repeat this process a few times in the fight. Also, if Snipe knocked them back, I can charge in while they are down and Power Burst them and retreat to a distance and start over. Also peppering him with power bolt/blast. This also gives me time to activate build up/aim without being hit. Many fights end up with me doing all the attacking while my foe is spending all his time getting knocked down and getting back up.
In team situations, it doesn't work as cleanly, but many times my aggro is limited to a small portion of the foes and I can sometimes use the same tactic of Power Push/Snipe in the middle of battles after aggro is drawn. I do suffer a higher instance of interrupt (actually any instance is higher because when I solo there is no one to interrupt me), but it works enough for me to continue to use it. If I do suffer an interrupt, I just use another attack OR I will target the nearest enemy (most likely the culprit of the interrupt) and Power Burst his butt which usually gets him away from me, as well.
I can't imagine playing without Power Push. Without it, Snipe would be limited to an initial attack only. With it, I have a big-hitter at my disposal at any point in a battle.
I slot Power Push with 2 ACC because everything is predicated on it hitting it's opponent.
