The quality of tomatoes, and indeed any vegetable, will usually reflect the quality of the soil or compost in which they are grown. Poor soil will inevitably produce poor vegetables and a good supply of well rotted manure or compost dug in will undoubtedly give you a better tasting crop next year. Some varieties of tomato can be tasteless anyway, regardless of the soil in which they are grown. If you like really tangy tomatoes, grow Gardeners Delight. They are a large cherry variety and are absolutely delicious. When grown outdoors they also ripen a little earlier than other bigger varieties.