The only PITA issue I have with the Google portfolio is that you cannot sell anything. As example you buy some shares in Aviva. You enter Aviva as LON:AV you then enter the amount of shares, the purchase date and the purchase price. You enter 100 for shares, the date and the price as pence 437.30 (UK stock prices like to mess you about with GBX and GBP) and it will show you the total value of your investment as £437.30. Happy days!
Now you decide you wanna sell 20 shares because you are skint and short of petrol money but there is no option to do so. You’d think: “easy, do it same as with the yahoo portfolio”, by entering the the share amount as negative (enter -20), transaction date and the amount you get, but then Google will not allow you to save that entry so you cannot continue.
If you try to enter the share amount as a normal positive value but you add the price amount as negative, then google adds that share amount to your total share count (now 120) for that stock, but deduct the value of sorts and the end results are totally wrong numbers and values.
This is the single most annoying drawback of the Google portfolio. To accurately record all buy and sell transactions the yahoo portfolio is much better. In Yahoo the ticker format is different example AV.L for Aviva.
The Google portfolio is kind to your eyes and the information displayed is easily digestible whereas with Yahoo it just looks complicated and you have to spend more time focusing on getting similar info compared to what you can pick up at first glance with Google portfolio.
Long story short; both Google and Yahoo portfolio tracking options are equally good and equally bad.
Yahoo looks crap compared to Google, but on Yahoo at least you can record sales.
If anyone does know how to record sell transaction s on Google, feel free to share the secret! 
Ooh! nearly forgot, @RayBBaby but on the Yahoo portfolio you can sort of add/track currency transactions or holdings you have by the looks of it. You enter the transaction values similar to how you would add shares transactions. Example ticker is GBPUSD=X