I tend to agree with Hank and Richard. The whole unde-rated/over-rated thing doesn't hold much water with me.
For example, how do you classify a unit such as my beloved 153rd PA? Both ny GG Grandfather and GG Uncle belonged to it. They were in 2 major battles - Chancellorsville and Gettysburg. At Chancellorsville they were one of only four regiments facing west, left to face Stonewall's assault practically alone. Never had a chance.
At Gettysburg they were the extreme right regiment of the entire Union line, and faced an assault by Ewell's entire division. Never had a chance, on top of being slaughtered by friendly fire trying to retreat. They had a commander who admitted hating them ( because they were of German/Dutch descent), so they were basically used as cannon fodder at both engagements. They're certainly not over-rated, and probably not under-rated. All I know is they had something that most of us in today's world don't. The guts to be in the thick of a brutal, heartless war. That's good enough for me.
If one wants to delve into some sort of analysis, that is one thing. All I really want is some attention given to the more obscure outfits. The 153rd PA is a great example. It sort of gets lost in the shuffle. Mention any XI Corps unit and the lack of study if them doesn't oaint a fair portrait.
Sure. Earlier I mentioned the units at Brawner Farm, but I'll give another example, the First Tennessee Cavalry. It served with Joe Wheeler and went on raids that beat anything that JEB Stuart's boys ever did. Then it got sent to VA and did some hard fighting throughout Hunter's Valley campaign and in the actions in southwest VA. Now, that isn't a slur on Stuart's much more famous outfits, like the 7th VA for example, or the 35th VA Battalion. But the 1st TN were in just as many actions and went on even rougher raids, as well as fighting as infantry in the nasty fighting at Piedmont. The odds they faced with the rest of Old Cerro Gordo's men at Blue Springs were terrific, but they get totally ignored.
For a Yank outfit, I nominate the 48th NY. That's probably the Union regiment I'm most interested in. They suffered very heavy losses on several occasions but are totally ignored. In fact, they suffered the largest percentage of casualties of any regiment in the second attack on Battery Wagner. Yet mention Battery Wagner and the only regiment that will come to someone's mind will likely be the 54th MA.