« any price would be a good entry point »
That has NOT been my experience, and I have traded BRK-B numerous times since 1998.
Would you have bought the shares I sold at a split adjusted $100.40 on 12Dec2007?
If you had, your cumulative return as of yesterday's close would have been 16.0%, which annualizes to less than 2.7%.
Clearly buying at a price to most recently reported book value ratio of 1.94 was not conducive to earning a decent return on your investment.
Right now and before they report their next quarterly earnings! Financials are doing well, which Buffett is invested in. So is housing. No major natural disasters, so their insurance business should be doing well.
This is a stock to buy with the intent of holding for a long time. Low beta so buy it anytime and hold it for years. Wait for a market dip if you want but you risk missing out on what is developing into a really nice bull run.
At the start of May, I did a quite conservative estimate of fair value and came to 117... it has gone up in value since then (including announcing one of the best quarters the company has had in its history, and several strong growth areas coming in). I have not done an estimate since then tho (so my 117 is even more conservative). I have been buying shares since then... I will need to run the numbers again relatively soon to see how much higher to go. If you are a very long term investor (one that wants to own a piece of the business for a long time and is not going to be overly concerned about the price day to day right now), I think up to 117 is quite safe.
If you are wanting a trade (something to buy today and sell in a day, week, month or even a year), then I do not know... market timing is certainly not my strength.
Good luck! :)