I've got 3 of the Lionel HO sets (Christmas passenger, Santa Fe Cajon and the NKP Fast Freight) and the Berks in each run really nicely. They seem to perform well, were built solidly and luckily the sounds all work well on all 3.
I would say that the negatives for me, which are minor, are that the engine seems to labor a lot when you increase speed past a certain point, where the chugging is a blur but the engine isn't moving any faster than a certain speed (I'm talking about if you turn the throttle way up); the wiring tether between the loco and tender is very thin and delicate (not a good idea if this is for a beginning model railroader or child) and (this one is major) the price still needs to be much more reasonable if Lionel wants to have any spot in the HO market. They already cancelled their first series of former Mantua locos (the Mikados) and this attempt in HO will be as short lived as their other efforts in the scale.
Back to topic, I really like the Berks. The detail is just right for a train set loco, it seems durable and has some nice features. At some point, I'm going to run them more frequently to see how they make out long term.
