So I loved BB Ace and sadly discovered it after it had already been discontinued. I've off and on searched for a replacement. Is the thinnest Lux string a substitute...let's find out.
BB Ace 112 v. ALU Power 115
Power: This is interesting, both strings have some nice little pop to them. Is it their speciality, no, but I think the thin guage really gives a little extra compared to similar thicker polys. I want to say that ALU felt like it gave a little more than Ace. It was subtle but especially in the sweetspot, you get a great sound off the stringbed and a hot ball. Both strings fell in a really good spot with a moderate power level but still a controlled response. No crazy launching or hotspots. ALU got a little less controlled as the time wore on compared to Ace, but they were pretty similar.
Spin: This, again, was pretty close. Ace to me felt like it had slightly more spin more easily. Was it due to the 0.03 difference in guage, I doubt it, but maybe. ALU wasn't lacking spin, it just felt like you had to work a little harder to get it. Good consistent racquet head speed and complete swings. Naturally this is all strings, but some really do require more from the user. I had a similar experience with Head Hawk. Ace just gave spin a little easier and a little longer. Both strings were losing snapback and ALU definitely lost a lot of its spin potential toward the end. Compared to all round polys, these were both pretty average. Neither really gave so much extra spin, they're really more control strings than spin strings, but they weren't bad for spin. They worked for my game and I think would generally work better in denser patterns. The latter is because if you use a dense pattern you are probably comfortable with the level of spin you get from your racquet and likely already rely on solid technique. The other part is they will last longer in a denser pattern. I got to about 75% notching in a denser 16x19 and am not an overly spinny player.
Control: As referenced in the Spin section, these are really more about control than spin. By that I mean you probably need to bring the spin with your technique. These help you control the ball. For me, I felt like I had better control and confidence with Ace. It felt easier to target and go down the lines than ALU. Maybe it is the tad bit more power that ALU felt like it had, maybe I was sensing it as power but really it was just less control. Was ALU bad, not at all, just didn't quite seem like I could target as well. For the thin guage, both strings had very nice control. The response is a little livelier than thicker guage strings but that doesn't equate to less control. The thin guage translates far more to feeling the ball on the strings and this helps with control from my perspective. As I said, these probably are better suited to a denser pattern too. A more open pattern the strings would probably start moving around too much and/or break quicker.
Feel: This is where the two strings largely differ and the main reason that ALU is, unfortunately, not a replacement for Ace. Ace has this lightly crisp but pure feel to it. ALU didn't quite feel as direct and didn't have the same light crisp feeling that Ace did. A very experienced ALU user described it as "gummy" and I think that fits. I had never really experienced it before, but now I get it. ALU is sort of gummy and dampened where you don't notice that it is so firm and the feel is clean. Ace is just pure feel and feedback with a light tempura crispness. Neither are uncomfortable, stiff, or dead but they are definitely different. Also, ALU somehow didn't feel quite as thin or not thin in the same way as Ace, I think it probably has to do with that gummy sensation. Surprisingly, after about 7 hrs, neither was really harsh or bad feeling. ALU definitely changed in feel more than Ace, but both have held up OK. Snapback has definitely diminished and they are a little pingy, ALU more so, but they're still playable. I'll elaborate more in the next section.
Tension maintenance/durability: This is the big one. Basically these strings double down, Luxilon is not known for tension maintenance at all. These strings are no exception and they're also really thin. After about 7 hours, both have lost tension and significant snapback. Basically after every ball strike the strings are staying out of place and this started at about 4-5 hrs. For notching, I estimate about 70-75% and I typically don't break poly. I intended to play these to breakage, ideally, but a TW playtest cut that short. I'd estimate it would have been at least 10hrs just because I'm not normally a poly breaker. For others or those with more open-patterned racquets you are probably looking at less than 10 hours. I'd say for some, the loss of playability and tension would coincide with breakage. Overall, you should know what you're getting yourself into using such a thin guage in terms of durability. As mentioned, a dense pattern definitely enhances the experience. Ace used to be my favorite string in my Ultra Tour. The dense pattern will provide more durability but you can't escape the tension maintenance. So these both score a low-average for tension maintenance.
Finale: The point of this was to see if ALU 115 could replace or serve as a substitute for the discontinued, but loved by some, Ace. Short answer, it can't. For a summary of reasons why, focus mostly on the Feel section. This is where they differ and the key reason ALU can't serve as a substitute. Honestly, more people need to use thin guage poly as I doubt the average user is breaking 125 or 130 guage. But in terms of that, ALU is a little disappointing too. It basically plays just like the other guages and didn't have that thin communicative feel that I get from other thin strings. I may just not be an ALU fan. Maybe the drop off experienced with thicker guages isn't as pronounced, so that's a possible benefit. Otherwise, I think my beloved PT Strike 1.20 is a closer replacement for Ace even though it's a little thicker and slightly dampened. If you're looking for an Ace replacement find something with a lightly crisp, pure/direct, undampened, non-plastic type feel.
Both tested at 48lbs in my Pro Staff 97s.