With the Thirty Years Wars it is usually perceived as Gustav II being this unstoppable giant, who beat Wallenstein at Lutzen and died unfairly. Then on the other hand there are those who idolize Wallenstein. There aren't too many sides beyond that, since Tilly never gets any love.
I would say that Gustav II and Wallenstein were fairly even. I think what carried Gustav II so well is that before entering the war in 1630 he took the time to reform his army along Dutch lines and then carry out some reforms of his own. This made his army the strongest in Europe at the time. He made short work of Tilly whose army wasn't up to par, and Tilly put up a very good fight at Breitenfeld.
Lutzen only happened because Wallenstein checked Gustav's victorious march into Bavaria, then Gustav withdrew into Saxony and Wallenstein camped opposite him, both going into winter quarters. Wallenstein thinking that was the end of the season, Gustav marched out trying to surprise attack Wallenstein but it didn't work, and then Gustav got killed leading a cavalry charge.
Wallenstein then trained an army along the lines of Gustav's reforms, his own version because he wasn't quite sure what Gustav did. The end result was the meat grinder at Lutzen. So I would say that Gustav and Wallenstein were very close in actuality. With Wallenstein having a much longer career than Gustav. But this is also where Wallenstein's career ended because the Emperor had him assassinated. Gustav was fairly aggressive, but could fall back on his defensive artillery positions. Wallenstein was an all around cautious general who liked to take up defensive posture, then react and maneuver if need be.
So basically it is Gustav or Wallenstein in the Thirty Years War. The problem with that view is that Tilly was really commanding before both of them to much success. Then Wallenstein took the field for a bit and was retired until Gustav showed up and defeated Tilly. After that we have a bunch of Swedish and Imperial generals. Also the Spanish intervened at that point, which adds another series of campaigns into the mix. Then the French intervened until the end of the war.
During those later stages we had Johan Baner, Lennart Torstensson, Carl Gustaf Wrangel, and Gustav Horn for the Swedes. The Spanish brought Cardinal-Infante Fernando, who would spend much of his time campaigning against the Dutch as well. There were a few Imperial generals but the most notable ones I would say are Franz von Mercy and Raimondo Montecuccoli. Mercy distinguished himself defending Bavaria, where as Montecuccoli would be more noteworthy after the war when he defeated the Turks and would go head to head with Turenne and Condé.
Which then leads me to the next segment. The French had a bunch of generals but the two that distinguished themselves the most were Condé and Turenne. I mean Condé twice defeated the Spaniards, but his campaigns in Germany showed his over aggression to be less effective against generals like Mercy. He was constantly tripping over Turenne, and didn't listen to Turenne's advice. He outranked Turenne and the one time that Turenne was given actual command he didn't have any supplies, an army that was falling apart, and then got ambushed by Mercy. Now Mercy died at the end of this war but Condé's reputation was soaring. Turenne was only a noteworthy.
Turenne really becomes famous afterwards during the Fronde when French nobles rose up against the Sun King (who was a child at the time), who were led by the King's uncle and various important lords like Prince Condé, the Prince of Conti, Turenne's brother etc. Turenne pretty much single handedly turned the tide of the war. Initially Condé and Turenne seemed evenly matched but Turenne managed to defeat Condé. Then Condé fled to the Spanish where he joined them in Flanders. Turenne chased after him and invaded Flanders where he defeated the Spanish at Dunkirk in 1658.
Then in 1667 Turenne invaded Flanders and defeats the Spanish again, overrunning all of Flanders. In 1672 the Sun King found himself at war with Spain, the HRE, and the Dutch. This would be Turenne's finest campaigns. He repeatedly defeated Imperial generals in Alsace. Defeated the Prussians at Turckheim in 1674, his best victory. Where Turenne basically attempted Gustav's earlier surprise march and succeeded. Invading as far as Berlin and raiding Germany all along his march, the farthest a French army had ever marched until that time.
He spent all of 1675 campaigning against Montecuccoli in western Germany. With the two marching and counter marching, lunging and parrying, sometimes Montecuccoli got the best of it. Finally in August Turenne was able to thoroughly outmaneuver Montecuccoli and had him cornered at Salzbach. When Turenne was on the verge of destroying the Imperial army and winning what might have become his greatest victory, he was struck by a cannonball and killed, the Imperial army managed to withdraw.
Condé for his part had fought a costly battle in Flanders against the Dutch, Imperial, and Spanish forces at Seneffe. The battle was indecisive and he was not in great standing with the court. However Montecuccoli followed up the death of Turenne by crossing the Rhine. Montecuccoli attempted to gain a foothold in Alsace. This time Condé fought defensively and maneuvered Montecuccoli as well as taking up a defensive posture. He managed to repel Montecuccoli's invasion.
Therefore it is hard to speak of the period without these other commanders. But especially the latter trio of Turenne, Condé, and Montecuccoli. I think it is clear that Turenne comes out on top over the other two. We can debate by how much. But when comparing these with Wallenstein and Gustav, I don't believe many would argue favorably in favor of Condé, nor would Monteuccoli really beat out Wallenstein as the greatest Imperial commander. I also didn't mentioned that these later wars were contemporary with Charles X of Sweden fighting Denmark and Poland. In this Franco-Dutch War (1673-1678), it was actually Marshal Luxembourg that basically ended the war favorably for the French. Then in the Nine Years War the same Luxembourg performed very well with battles like Fleurus in 1690.
