My experiences with limi's is that they are fairly fast growing... so am a little surprised by your comments about them maturing slowly. I find Simmentals to be slower growing/maturing, and getting big.
The limi jersey crosses will mostly tend to be a little smaller towards the jersey size than the limi size.... but the steers tend to grow pretty good. They all seem to have had a little lighter bone structure than the straight beef... but again, some will take after one side and others after the other side. Right now I have 2 hol/beef steer calves, along with the cow's own calf, on my nurse cow. Both out of heifers on one of the dairy farm's I test, both are 1100+ lbs as first calf heifers... good big heifers. Milking good last month. One is angus sired, and the other is a limi sired. The limi is more brownish tint, has more muscle and more weight... the angus is smaller and narrower, jet black.... just 2 random calves bought off a dairy to put on the nurse cow along with her calf. I needed 2 and these 2 were born 1 day apart. All 3 come in for some creep feed and I see all on the cow together.... So you never know. And the limi one is friendlier and comes up to get scratched when I put feed in the bunk for them... the black is a little less accepting and her own calf is a very standoffish little witch. She is 1/2 angus also.
Granted this is a very small comparison group.... but it is totally random. I get small groups/pairs like this most times... get what is available at the time I need them.